The Heart of Boswell: Six Journals in One Volume, by James Boswell; edited by Mark Harris (McGraw-Hill, $7.95). James Boswell was the author of the greatest biography in the English language (The Life of Johnson) and at the same time, through his journals, the author of the greatest autobiography. Here is a condensation of the first six volumes of the journals which begins with the 22- year-old Boswell's arrival in London from Scotland, continues through his grand tour of Europe, and ends as he finds a wife and tries to settle down in Edinburgh. Boswell's sensibility is decidedly modern and to read him is to become an enthusiastic admirer.

Psychoanalysis: The Impossible Profession, by Janet Malcolm (Vintage, $3.95). When it was published in The New Yorker, this short, elegantly written history of pyschoanalysis attracted much attention. The author explores "the talking cure" with a New York psychoanalyst she calls "Aaron Green."

Wall-to-Wall America: A Cultural History of Post-Office Murals During the Great Depression, by Karal Ann Marling (University of Minnesota Press, $14.95). During the Depression of the 1930s, hundreds of murals were painted in post offices under a program of the Treasury Department Section of Fine Arts. This learned, highly entertaining essay in art history imaginatively explores popular taste in the '30s. Learn how the program's administrators were shocked to learn that nudes were going to be painted in the Richmond, Virginia, post office.

Nietzsche: A Critical Life, by Ronald Hayman (Penguin, $6.95). Ronald Hayman in this lucid biography approaches the thought of the influential and often misunderstood 19th- century German philosopher through his life, believing that "his philosophy cannot meaningfully be separated from his friendships and quarrels, his illnesses and depressions, his teaching and his letter-writing." Nietzsche himself wrote that, for the best writers, "thinking constitutes the involuntary biography of a soul."