Stumbling on Happiness is a nonfiction book by Daniel Gilbert, published in the United States and Canada in 2006 by Knopf.

[1] Gilbert's central thesis is that, through perception and cognitive biases, people imagine the future poorly, in particular what will make them happy.

The book is written for the layperson, generally avoiding abstruse terminology and explaining common quirks of reasoning through simple experiments that exploited them.

[2]: 65  Finally, given the imperfections in self-reported feelings of happiness, scientists must rely on the law of large numbers, namely, to ask many people the same question and compare their answers.

[5] Gilbert says, “A healthy psychological immune system strikes a balance that allows us to feel good enough to cope with our situation but bad enough to do something about it”.