THE AWFUL TRUTH ABOUT PUBLISHING: WHY THEY ALWAYS REJECT YOUR MANUSCRIPT AND WHAT YOU CAN DO ABOUT IT by John Boswell (Warner: $14.95; 161 pp.). A literary agent, book packager and part-time writer, John Boswell has sought to provide a quick fix on the American book trade, nudging and winking his way through common misconceptions beginning authors have about publishers' decisions to publish and their subsequent decisions relating to distribution, promotion and advertising. He has produced instead, "The Cheshire Cat's Guide to Smiling." His tone is reminiscent of those full-paged newspaper ads wherein millionaires plead for the chance to share their secrets with us. With the exception of the appendix and a sample of a successful book proposal, much of this work is readily and more reliably available in Publishers' Weekly and writers' magazines. Even the appendix was better done by Samm Sinclair Baker in a past issue of The Writer.