WAITRESSES: AMERICA'S UNSUNG HEROINES by Leon Elder and Lin Rolens (Capra: $8.95; photographs). What essayist-artist Alexander King was to the garbage collector--each night, somewhere, presumed King's statement on personal satisfactions, a man sits down to a kitchen dinner, and his weariness and humility is lessened because he knows he has hefted more garbage cans than any other man in the world--authors Leon Elder and Lin Rolens are to the waitress: her devoted servants and doting enviers. "Waitresses: America's Unsung Heroines" elevates to professional peerage all who have worn and suffered starched minis and pinnies, from the Harvey Girls of the 1880s to Alice and her sitcom of the 1980s. Each, says Rolens, herself a 10-year veteran of the catsup and varicose circuit, is a Geisha-Nurse-Mother figure. Bless 'em all, adds Elder, from gritty truck stop to Art Deco eatery, who have ever hefted a hamburger with side orders of concern, humor, stamina, anticipation, athleticism, flirtation, maternalism and sympathy. The book--although suggesting no prizes for layout and graphics--is a collection of cute observations from the customer's point of view, some cutting reportage from the waitresses' side of the short order scene, and consistently perceptive writing by Rolens. Try this: "Near my university I carried beer and pizza at a side-street place managed by a fading Dodger hero. The departments came in groups: chemistry drank the most, the philosophy and English departments tended to play with their food and the physicists laughed to themselves as though they knew secrets and were not about to tell. Though I worked my way through six years of university, most of my useful education I received while waiting tables. To this day I can spot a turkey sandwich when it walks through the door." Wonders Elder: "What mystifies me most of all is how a waitress can run the gamut of gaping mouths, lascivious cooks, truculent bartenders, paranoid owners, indolent busboys and hot plates and still be Miss Cheerful." So one read of this monograph and you'll never tip only 10% again.