The good fortune would not cheer me up for very long, while even after the most tragic events, I'd be back, shockingly soon, to daydreaming happily about dinner menus or sex in exotic climes. These two books set out to explain why most of us are so dead wrong, so often, about what will give us happiness.

Gilbert is a Harvard University psychologist who specializes in "prospection," the study of how we think about our futures. Ricard is a Buddhist monk whose research focuses on how meditation affects brain chemistry. Needless to say, they have different takes on the science of satisfaction, although they agree about some principles -- that love is good for you, for instance, and that money can't buy you love.

Since Ricard left Paris and a promising scientific career to "achieve genuine inner freedom" and has lived in the Himalayas for the past 35 years, his rejection of the trappings of consumer culture is to be expected. Happiness outlines a crash course on Buddhist meditation, which allows us to enjoy "experiences in the context of a vast and profound serenity." Modest and earnest, Ricard does not claim to provide new information but rather summarizes the body of thought that already exists. The book's freshest terrain is the intersection of Buddhism and the field of positive psychology, pioneered by Martin Seligman, who studies the roles of optimistic and pessimistic outlooks in personality.

Ricard quotes Seligman so often that readers may be tempted to go straight to Seligman's classic, Learned Optimism , which covers much of the same ground.

Obviously, Ricard believes that the ability to transcend adversity is critical to personal happiness, and he explains why some Tibetan victims of torture have rosier outlooks than the average middle-class American. Whether Happiness would help most of us take even baby steps up the long road to enlightenment I'm not so sure. It's hard for a diehard ironist to imagine, say, Larry David of "Curb Your Enthusiasm" fame trying Ricard's exercise for letting "any inner tension dissolve": "Savor the warmth and joy that result from a calmer mind. After a while your thoughts will become like a peaceful river. If you practice regularly, eventually your mind will easily become serene, like a calm ocean. Whenever new thoughts arise, like waves raised by the winds, do not be bothered by them. They will soon dissolve back into the ocean."

Gilbert is a professor by trade, but he's every bit as funny as Larry David. Stumbling on Happiness may be one of the most delightfully written layman's books on an academic topic since Robert M. Sapolsky's Why Zebras Don't Get Ulcers . Gilbert translates and makes sense of a vast array of scientific literature on perception, memory and imagination. Among other things, Gilbert explains why we learn so little from our mistakes -- why so many divorced people wake up realizing that their second spouses are exactly like the ones they left. He reviews some common tricks of memory, such as our tendency to "remember the best of times and the worst of times instead of the most likely of times," and some kinks in our decision-making processes, like our tendency to rationalize.

Almost every page of Stumbling on Happiness delivers enjoyable riffs such as this one, in which Gilbert discusses the distinctly human delight of imagining we can control our futures:

"The act of steering one's boat down the river of time is a source of pleasure, regardless of one's port of call. Now, at this point you probably believe two things. First, you probably believe that if you never heard the phrase 'the river of time' again, it would be too soon.

Amen. Second, you probably believe that even if the act of steering a metaphorical boat down a clichéd river is a source of pleasure and well-being, where the boat goes matters much, much more. Playing captain is a joy all its own, but the real reason why we want to steer our ships is so we can get them to Hanalei instead of Jersey City."

Much of the giddy fun of Stumbling on Happiness comes from the sheer nuttiness of some of the reported experiments. Real researchers -- at Gilbert's own Hedonic Psychology Laboratory at Harvard, among other places -- are running carefully calibrated studies on questions like whether people respond differently to the prospect of spaghetti and meatballs for breakfast or dinner when they are hungry or when they are full.

They are showing pictures of amputations and car wrecks to normal people and to people suffering from alexithymia (the "absence of words to describe emotional states"). But Gilbert convincingly shows how such studies manage to derive useful scientific data on our very subjective perceptions. He also proves how deeply we cling to the cherished notion of how "special" we are -- which is exactly why we are so loath to take advice from all of those other souls we dismiss as average. ·

STUMBLING ON HAPPINESS
By Daniel Gilbert
Knopf. 277 pp. $24.95

HAPPINESS
A Guide To Developing Life's Most Important Skill
By Matthieu Ricard
Translated from the French by Jesse Browner
Little, Brown. 281 pp. $22.95

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Lisa Zeidner's most recent novel is "Layover." She is a professor of English at Rutgers University.