The arrival of summer brings certain peculiar activities in which millions of Americans merrily participate, even though all the evidence indicates that none of them is in the least bit beneficial to human health. These millions lie in the sun, they soak in salt water, they drink gin mixed with quinine water, and they read books.

Ah, yes: summer reading. It's a quaint American custom designed to exorcise all the literary guilt accumulated over the rest of the year. People who from September through May have little time or inclination to take the plunge into books suddenly are reminded, as the solstice approaches and the humidity rises, that reading really can be fun, or profitable, or even both. In June people wrap themselves in literary projects, just as in January they wrap themselves in resolutions--probably with much the same results.

If the plans of June are rarely realized by Labor Day, that's because Americans insist on taking the wrong kind of book on vacation. They load down the car with Proust and Faulkner and Dostoevski and Hardy, when what the weather and the circumstances call for is more easily digested fare. Summer reading should be intelligent and literate, and if it adds to one's storehouse of useful or useless knowledge that's all to the better, but mainly it should be entertaining; taking the work ethic to the beach is, after all, a most peculiar form of relaxation.

To be sure, one reader's entertainment is another's torture; it's a lot easier to define what constitutes pleasurable and rewarding summer reading in general terms than to assemble a list of specific books upon which a dozen readers would be able to agree. Yet all vacationers except those hell-bent on self-improvement probably would acknowledge that the chief purpose of summer reading is escape. We want summer reading to do what the beach does: take us away from it all. And contrary to what seems to be the widespread assumption, it is not necessary to seek out second-rate books in order to make a first-rate escape.

With that thought in mind, I went through my bookselves the other day in search of titles which, had I a non-working vacation in prospect, I might bring along. I ended up with a list that would keep me, if no one else, in a state of euphoria. Its contents--primarily but not exclusively works of fiction--fall into several broad categories: spy stories, mysteries and other works of suspense; books set in faraway places, preferably exotic ones; satire, slapstick and other forms of humor; long, populous novels into which one can sink for days; and memoirs of mischievous and/or misspent youth.

In the category of suspense, one of my early choices, Martin Cruz Smith's imaginative police-procedure novel, "Gorky Park," has only recently appeared in paperback. I am not a devoted reader of mysteries or crime novels, but there is plenty of room in my world for anything by Dashiell Hammett or John D. MacDonald, and I can report that MacDonald's new Travis McGee adventure, "Cinnamon Skin," finds the bard of Florida at his best. But if I had room in my valise for only one mystery, it would be Josephine Tey's "The Daughter of Time."

Never having caught the Eric Ambler habit--it's my fault, not his--I turn to John le Carre' and Graham Greene for the sordid thrills of espionage. "The Spy Who Came in From the Cold" is still le Carre''s best novel, but all of the George Smiley novels are elegantly diverting--though untangling the plot of "The Honourable Schoolboy" is the kind of work one should not have to do on vacation. As for Greene--who depending on the day of the week and the state of the Union is or is not my favorite living novelist--there are untold riches from which to choose. "The Confidential Agent," perhaps, or that divine comedy, "Our Man in Havana."

Or, for that matter, "The Honorary Consul," which is not exactly a spy novel but which moves us smoothly into the second category; like almost everything else in Greene's vast canon, it takes the reader to an exotic locale that he almost certainly will never visit. The same is accomplished by many of the works of Greene's literary heir, Paul Theroux, the best of which are "Saint Jack," "The Great Railway Bazaar" and his most recent, "The Mosquito Coast." For three decades I have been sailing the oceans of the world with C.S. Forester, whose Horatio Hornblower novels (the best are "Beat to Quarters," "Ship of the Line" and "Flying Colors") are proof positive that it's possible to be swashbuckling and literate at the same time. Christopher Buckley's "Steaming to Bamboola" is seafaring of a quite different sort, but it won a permanent spot on my shelves immediately upon publication this April.

Not merely does Evelyn Waugh journey to foreign climes, but he is arguably the greatest comic novelist of the 20th century; if I could take only one Waugh it would be "Men at Arms," for its stupendous exploding thunderbox, but just about any Waugh will do. Ditto for Peter De Vries; "Comfort Me With Apples" is delicious, as is "I Hear America Swinging." Wilfrid Sheed is not exactly a comic novelist, but "Office Politics" is a terrific comic novel; so are Kingsley's Amis' "Lucky Jim" and William Boyd's "A Good Man in Africa." If you prefer your humor in small doses, James Thurber and E.B. White are obvious choices; but how many remember their colleague Wolcott Gibbs, whose "More in Sorrow" contains some of the best satire in the American language? Nora Ephron and Calvin Trillin also are obvious choices; but let us not forget Roald Dahl, the master of the hilariously macabre, especially in "Someone Like You."

There's much humor in the work of my favorite novelist of manners, John P. Marquand, but he's primarily to be read for the pleasures of sinking into books that are amply supplied with the stuff of real lives; try, for a change from the ones usually recommended, "So Little Time" and "Point of No Return." I wish Calder Willingham would resume writing long, fat novels, because in their somewhat weird fashion "Eternal Fire" and "Providence Island" are quite wonderful. So, though I shall be consigned to damnation for saying so, is "Gone With The Wind"; overlook the racial attitudes characteristic of Margaret Mitchell's time and place, and revel in her passionately human story. Southern emotions of a different order, but equally powerful ones, are on display in Pat Conroy's "The Great Santini." Books that I liked as a teen-ager, and still like as an adult, are "The Caine Mutiny" and "The Last Hurrah." And have you ever actually read "Tom Jones"? Albert Finney can't hold a candle to Henry Fielding.

Finally, I happily admit a weakness for books that in one fashion or another return me to the joys--and the agonies, too--of boyhood. I grew up on Thomas Bailey Aldrich's "The Story of a Bad Boy" and Booth Tarkington's "Penrod and Sam," and the mere mention of them commands me to reread them. The same goes for Robert Graves' "Goodbye to All That," Clive James' "Unreliable Memoirs" and--the very best of a very good batch--H.L. Mencken's "Happy Days."

Let's see: that gets us through the middle of July . . .