One doesn't usually think of Marcel Proust as the author of a great self-help book. Unless of course what you admire most about ''Remembrance of Things Past'' is its usefulness for killing huge amounts of time.

Alain de Botton, a novelist, doesn't take quite such a crassly utilitarian view in his delightfully original work of literary criticism, ''How Proust Can Change Your Life: Not a Novel.'' But he does come close in places. For instance, in Chapter 3, called ''How to Take Your Time,'' he points out that one reaction to the great length of Proust's famous novel was the ''All-England Summarize Proust Competition,'' once presented by the Monty Python troupe in the belief, as Mr. de Botton puts it, that ''what had originally taken seven volumes to express could reasonably be condensed into 15 seconds or less, without too great a loss of integrity or meaning, if only an appropriate candidate could be found.'' . . .