ark McDonough has a boyish face, outsize eyebrows that dance like dragonfly wings when he speaks and an awful lot of money. He makes a point of not revealing how much -- not to me at least, or to you. But he has more than he will ever need. Because he did not earn the money himself, however, he has a rather complicated relationship with it. He sometimes calls the money ''the monster that jumped into my bed.''

He grew up in Paxton, Mass., an hour west of Boston, one of two sons of a hard-working father who made a fortune in plastics. Although it took a long time for McDonough's mother to stop clipping coupons, the family eventually assumed a solidly upper-middle-class life. ''My parents would say, 'Well, you know, you are rich,''' he told me. ''I'd say, 'Yeah, sure,' but I hadn't seen any of it yet.'' After college at Vassar, he earned a master's degree in business at the Sloan School of Management at M.I.T. and started a company that developed a computer database. He married, had a daughter and was heading toward a divorce, all without having seen any family money.

It was during his divorce negotiations that he was compelled to tap into his inheritance. He did this reluctantly. ''One of the family rules was that you don't ask for money,'' he said. ''It's there, but you don't ask for it. You're rich, but you're not rich.'' His parents freed up enough money for the settlement. A few years later, when his share of the family business began to be liquidated, he was suddenly a wealthy man. By then he had earned another master's degree, this one in marriage and family therapy, and he was counseling welfare families outside Boston. ''Welfare people and inheritors have a lot in common,'' he told me. ''They both know they can't survive on their own.''

McDonough, 47, speaks excitedly and discursively. With the zeal of a reformer, he relishes telling his cautionary inheritor's tale.

''So first of all,'' he said, ''there's this closet called the Green Closet. It's one of the last taboos. This culture tells you, if you have more money, you'll be happier. But rich people are in this unique position to say: 'You know what? More stuff doesn't mean more happiness.' But as a rich person, you absolutely cannot tell anybody that there's anything wrong with your life because, first, everybody knows you should be really happy, and, second, they say, 'I should have your problems!' Then there's the shame component. With inherited wealth, there's this little logic chain: I have a lot of money, I should be really happy, but I'm not happy, so I must be really bad.''

In 1986, John L. Levy, a sort of freelance philosopher, wrote a monograph called ''Coping With Inherited Wealth.'' It was one of the earlier works in what has become the crowded literature of ''affluenza.'' Levy laid out the traits common to many children of wealth: low self-esteem and self-discipline, difficulty using power, boredom and alienation and guilt and suspiciousness.

McDonough fit snugly into Levy's template. He found himself investing and giving away money recklessly. ''I felt I needed to right all the world's injustices,'' he said. ''If you could make a valid case as to why not having money was an impediment in your life, I'd just open up my wallet.'' Above all, he says, he felt guilty. ''It was sort of this Holocaust-survivor thing -- 'Why me? Why did I get to have all this and others did not?'

''And then,'' he said, ''I magically bumped into someone who felt like, Why not me? Now this Why Not Me felt she should have a big chunk of my money, and since I was Why Me, she got a big chunk of my money. When you're bedding down with someone, it's very hard to say no.'' McDonough's new girlfriend was capable of spending thousands on catalog clothing in a single phone call. ''I told her that I came into a lot of money but I didn't know how to enjoy it. She was willing to teach me though, and I signed up for her course. We went on some very expensive vacations that just made my toes curl.''

It wasn't as if McDonough hadn't known he would come into money someday. Nor was he what estate lawyers call ''a waiter,'' an heir who never gets on with life, in anticipation of the money's arrival. He was a good example, in other words, of the modern inheritor. People like him bear no resemblance to Richie Rich. They have not been steeped in a culture of wealth and entitlement; they have not been cocooned from the hurly-burly. They are not accustomed to being with money and handling it. They often feel uneasy if they step up a social rung or two. They see their friends, and maybe even their spouses, looking at them differently. They look at themselves differently.

It is an axiom of economics that the more options you have, the better off you will be. But psychology argues otherwise (as does common sense). It seemed that for McDonough, sudden wealth produced too many options. It removed all the rules and conventions and constraints. He found that he couldn't affix a value to anything. Sure, the money belonged to him, but it didn't really feel as if it did. The money was running him, not the other way around.

There are a lot of Mark McDonoughs in America, and many more on the way. They are the offspring of the postwar workhorses who made rubber gloves and cardboard boxes, who sold lumber and life insurance, who built shopping centers and consulting firms and medical practices. They will also increasingly be the children of the aging baby boomers, heirs to the mountains of money that that generation accumulated. Some of this money has already been passed along. Eventually, of course, it all will, and will amount to the largest transfer of private wealth in history.

The dot-com boom may have been spectacular, but it was one torrential cloudburst, with a savvy or lucky few sticking out their buckets before it ended. The Great Wealth Transfer -- as it is breathlessly called by financial advisers, estate lawyers, tax collectors, philanthropy directors and assorted ''wealth counselors'' -- will be a steady, soaking rain for decades. A 1999 report by the Social Welfare Research Institute at Boston College estimated that at least $41 trillion, and quite possibly double or triple that amount, will change hands by 2052. More than six million estates of $1 million and above will be settled.

The federal government stands to take its trillions (depending on the future of the estate tax). As does the nonprofit sector (again, depending in part on the estate tax, which is the impetus behind so much charitable bequest). But those are the broad landscapes, where even broad changes can be hard to appreciate. The more vivid dramas will play out among individual heirs and their families.

''We're just beginning to see how this is going to impact everybody,'' says Robert Kenny, the executive director of More Than Money, a peer network and support group for philosophically inclined wealthy people (including Mark McDonough). ''Let's say you're a boomer, in your 50's, and the transfer happens now from your parents. The tuitions are paid, the dentist's paid, you already have the second house. Now all of a sudden, there's this chunk of money. What are you going to do? Lots of people move to Malibu, and they're bored out of their skull.''

More Than Money is one sort of group that will probably thrive as the Great Wealth Transfer unspools. Founded in 1991, it has about 1,200 members trying ''to explore the impact of money in their lives,'' as the literature puts it, ''and to act on their highest values.''

Among the group's guiding lights is Paul Schervish, a sociologist of wealth and philanthropy and co-author of the Boston College wealth-transfer report. A former Jesuit, Schervish is sharp-thinking and plain-spoken. He is a devout proponent of philanthropy but doesn't like the way fund-raising is often practiced. ''There's this continuous bullying of the donor,'' he told me, ''and this back-room discussion that uses such terms as 'roughing up the donor,' 'prospecting,' 'cultivating,' 'closing.' It's a sales mentality.''

A significant inheritance, Schervish told me, can easily be a life-scrambling event. ''It's what I call temporal empowerment,'' he said. ''It's the ability to reshape your past, attend to the present and chart a future according to your will.''

But what might that future look like? Money may be many things to many people, but it is never neutral. Americans in particular seem uncomfortable with the notion of having ''enough'' money; there is only too little and, for a growing minority, too much. Having too much may solve certain problems, but it tends to create others, some of them purely emotional.

''Money finds the cracks in a relationship,'' one inheritor, a woman in her early 30's, told me. Her husband -- now her ex-husband -- insisted that money wasn't important to him, but he got upset when she kept her assets in her name alone. ''Particularly for women,'' she said, ''it's very hard to be the one with the money.''

Jeff Weissglass, chairman of More Than Money, came into family money sooner than he expected, or wanted: within the space of two years, his father and both of his wife's parents died. Weissglass had already downshifted from a Wall Street law career to a job in community-development banking in Chicago. Now the new money left him feeling ''like an outsider,'' he said. ''It's a fear of being not seen as a whole person when you let it be known that you don't have this issue in your life that's such a dominant part of the lives of most people.'' When he's not working for More Than Money, Weissglass, 46, is now primarily a parent. He especially dislikes the odd looks he gets when he's the only father in his kids' playground; he admits that he doesn't like appearing ''unaccomplished.''

This need for self-actualization -- a phrase you may recall from Psych 101, sitting atop Abraham Maslow's famous pyramid of human needs -- is what most consumes the inheritors I spoke with. They tend to have opted out of the sort of work responsible for the money they now own. As McDonough put it, ''There was no satisfaction in making the pile a whole lot bigger.'' And so . . . what now? What sort of life becomes an heir most?

One inheritor I spoke with, a man in his mid-30's, briefly followed his hard-charging father into the investment world. But after two years there, and a few more years meandering, he recast himself as a consultant to nonprofit organizations.

And what, I asked him, does your father think of your work? A strange sound came out of him, somewhere between a grunt and a sigh. ''Boy,'' he said, ''can you find that out for me?''

New wealth also presents the practical issue of fending off the multitude of opportunists, speculators and hustlers who would gladly be your new best friend for, oh, just a 1.5 percent commission. This perpetual pressure would explain the curious ground rules at a More Than Money conference I visited in early May. Attendees were required to sign confidentiality and nonsolicitation agreements. (Financial advisers have been known to try joining the group to troll for clients.) They were encouraged to remove their name tags whenever entering the hotel's common areas. Placards bore More Than Money's logo rather than the group's full name. ''Our hope,'' a handout explained, ''is to minimize the use of provocative language that might elicit unwanted questions from outside of the M.T.M. community.''

A few days after that conference, I attended another one, held at a golf resort in Palm Beach Gardens, Fla. It was for the people who want to help the Mark McDonoughs of the world handle their new reality, actualize their new selves. It was a meeting of the Sudden Money Institute, a coalition of financial advisers, psychologists, accountants, philanthropy advisers and estate lawyers trying to make sense of -- and get their piece of -- the Great Wealth Transfer.

The institute is the invention of Susan Bradley, a longtime financial planner and author of ''Sudden Money: Managing a Financial Windfall.'' Bradley is blond, confident and a fast and engaging talker with a whisper of a lisp. ''I'm not here to make my millions,'' she told me. ''It'd be nice if that were to happen. But I'm here because this is a personal and collective mission.'' The mission, as stated in the conference program, is ''to create a space to dissolve the boundaries that separate our professions and focus on the interior side of wealth together.''

It is never easy for a hard-sell business to get in touch with its soft side. But that is what the Sudden Money Institute -- and the entire financial-services world, it seems -- is trying to do. As money grows ever more central to American culture, and as ever greater doses of psychology are injected into the world of money, financial advisers are making the claim that they are, in effect, the new generation of therapists.

The Sudden Money gathering, however, never felt as much like a meeting of the minds as like a sales conference. Which is what, for all its aspirations, it was. A panel discussion about ''wisdom communities,'' for instance, featured the president of the Institute for Certified Divorce Planners and a long-winded estate lawyer who plainly came to collect referrals. The notion that we were there to dwell on ''the interior side of wealth'' was not helped by the fact that the meeting room overlooked a luscious swimming pool, and that every presentation was punctuated by the clack-clacking of golf shoes en route to the pro shop.

A low-grade anxiety, meanwhile, seemed to creep into every corridor conversation. As vast as the Great Wealth Transfer will be, the cottage industry to which the Sudden Money people belong is becoming severely competitive. More and more psychotherapists, their practices wounded by managed care, are repositioning themselves as ''wealth coaches.'' Even the banks and brokerage houses have begun to offer warm-and-fuzzy financial planning. I couldn't help feeling a twinge of concern for the future Mark McDonoughs, besieged by so much financial psychobabble.

Robert Kenny, of More Than Money, came to the Sudden Money conference reluctantly -- out of professional courtesy, he told me -- and by the end of it, whatever enthusiasm he had was spent. Trained in counseling and educational psychology, he is all in favor of candid conversations about money. But shilling and carping wasn't what he had in mind. And too many people there, whether they would admit it or not, were dying to get hold of his membership list. All those thoughtful millionaires, just begging for guidance.

A few days afterward, I caught up with Kenny by phone. When I asked just how aggressively he had been courted at the conference, he laughed. Very, he said. But at least it had been a learning experience: ''It's the closest I'll ever get to feeling how my membership feels every day.''

Mark McDonough didn't last long as a welfare-family therapist. He did, however, recently break up with Ms. Why Not Me. It has taken him several years, but he finally learned that he has the right -- and the need -- to say no. He is no longer a walking wallet for needy friends or slapdash philanthropists. ''I have my spiel now,'' he told me. ''I say, 'I've come to understand that I have many charities, and one of them is not you.''' He has even started enjoying his money -- a little bit. ''One of the ways I know I'm rich is, when I go to the W Hotel in New York, I decide to buy the high-speed Internet access for $14.95. I still have a hard time spending the $14.95, but I just do the sign of the cross over it and say, 'I can afford this.' You stop doing those eternal calculations.''

Money is the puzzle of his new life, and he has begun to solve it. ''You either grow it or you give it away, but you need to keep it flowing,'' he said. ''If it's just sitting there, you're living in fear. Fear that it'll run out.'' He is openly awestruck by the creative philanthropy being practiced by some other inheritors he has met. ''Generosity takes away your fear,'' McDonough said. ''But I'm not ready to give away all my money yet. I'm still trying to own it first.''

For now he stays busy with a serious hobby, a pair of astrological-database Web sites he built. He's keeping his eyes open, meanwhile, for a philanthropy that turns him on. And, perhaps, for a wife.

''I've come to realize that having money is my ethnicity,'' he said. ''In the same way you say you're Irish-American or Italian-American or Jewish-American -- it doesn't say everything about who you are, but it does tell a lot about your character. It gives a clue about the culture that you come from. It's the same way with money. But here's the trick: We all want to be loved for who we are, not what we've got.''