Putting on the Dog To celebrate Peanuts' 40th anniversary (1950-1990), Abrams is publishing Snoopy Around the World. Snoopy and his sister Belle-the stuffed, plush versions-were photographed against exotic backdrops, decked out in duds created especially for them by the world's top designers. Charles Schulz wrote the captions. The book accompanies an exhibition of the actual haute canine couture (currently in Los Angeles at the County Museum of Natural History). The beagles strut some bright Emanuel Ungaro stuff in Washington; cavort in front of the Colosseum in Rome wearing Giorgio Armani suits; snuggle in Porthault beach wraps on the Riviera. Did designers find it hard make such short clothes? ''It wasn't so much the height, it was the waistline,'' says Geoffrey Beene. Where There's Smoke Former first daughter Patti Davis has signed with Carol Publishing for a novel-her third-about a strained mother-daughter relationship. The Los Angeles Times described her last fictional effort, Deadfall, as a ''political Daddy Dearest.'' This one, tentatively titled Smoke Signals, is due out in spring 1992.

Book for Sail Walter Cronkite is doing a different kind of anchoring these days. He has just finished Westwind (Oxmoor House, $60), his third sailing book with Ray Ellis (Cronkite writes; Ellis' paintings illustrate the text). Although he looks every bit the old salt, Cronkite, 73, didn't learn to sail until he was in his 50s-and the first time he set foot in a Sailfish, he capsized it. Presumably he's more expert now. He and wife Betsy have graduated to a 48-foot cruising ketch, the Wyntje, named ''after the first woman who married a Cronkite in 1642 in New Amsterdam in honor of all women who've made Cronkite men happy ever since.''