It's so compact it could fit in your cargo pants, yet it's crammed with tons of ad nostalgia for those glorious days of yore, like 1948, when the Sunshine Baker man was a guy in a chef's suit who must've weighed 400 pounds. It's Meet Mr. Product: The Art of the Advertising Character, a $16.95 paperback, by Warren Dotz and Masud Husain, new from Chronicle Books. Yes, it's got an exclusionarily sexist title, but let's cut this little tome some slack, it's a retro subject. And there are plenty of chicks on hand. Miss Freshway Beverages, of 1936, looks like a total party animal, and 1952's Miss Curity, "The first lady of first-aid," could resuscitate a corpse. We don't even want to think about the bare-assed Little Miss Coppertone of 1956, which today is the stuff of Pete Townshend's hard drive. Seen here: Bob's Big Boy, 1950, when burgers were serious man-food.