For anyone who's ever wondered how the Oh Henry! Candy Bar got its name, or whether, as minor has it, Humphrey Bogart posed for the picture of the infant in Gerber's Baby Food ads, or just what makes the self-adhesive tape ""Scotch,"" Morgan's Symbols of America has the answers. By selecting and then researching hundreds of commercial trademarks, ranging from the oh-so-familiar to the tantalizingly obscure, and telling the stories behind many of them, Morgan has created a compendium of American popular culture that's always informative, frequently hilarious, sometimes shocking, and as irresistible as Crackerjack. (For the story of ""Crackerjack,"" incidentally, see page 139.) The author has divided his selections into more than three dozen categories. In Part I, ""Visions of America,"" the headings include Patriotic Symbols, Famous Faces, and Sports, among others. Part II, ""Symbols of Commerce,"" covers such topics as Liquor, Snack Food, Office Supplies, Clothing, and Publishing and Entertainment. One of the most revealing concerns racial stereotypes as expressed in advertising. In this area, Native Americans (Calumet Baking Powder and Land O' Lakes Butter) seem to have fared better than Blacks (Aunt Jemima Pancake Flour and Gold Dust Washing Powder) and Orientals (Rough-on-Rats and Yaller Kid Candy). Happily, these virulently racist ads would be unthinkable today; it's important to know they existed, however. Morgan's prose style is sprightly, as might be expected from the man who, a few years ago, penned The Shower Song Book. He spins his anecdotes with assurance and a finely-tuned sense of pace. The material never becomes repetitive in the telling nor does Morgan try to invest it with undue ""significance."" He obviously enjoys these stories himself and is delighted to share them. Symbols of America is intelligently laid out; categories are clearly organized and a complete index of product names makes finding favorite anecdotes and graphics simple. In addition, an exhaustive bibliography encourages further explorations in the field. A diverting discovery for devotees of American curiosa, especially those intrigued by the behind-the-scenes workings of big (and little) business.