Subtitled: ""Selections from the column that became an institution in The New York Times."" (That spot on page two in the Book Review section still seems empty.) For over thirty years, Mr. Adams supplied his weekly essay on books with opinionated distinction. In this selective collection, he has allowed himself the reviewer's luxury -- going back over contemporary comment and updating it with forewords that show how his position or judgment has been modified by time. The columns have been grouped by subject -- fiction, biography, autobiography etc. It's a bookman's good book talk and altogether, a personal panorama of the popular book in the 20th century.