MEET THE MERTZES: THE LIFE STORIES OF I LOVE LUCY'S OTHER COUPLE

''I loathed William Frawley,'' Vivian Vance revealed in 1962, adding that she ''raced through'' each new I Love Lucy script, ''praying that there wouldn't be a scene where we had to be in bed together.'' Apparently, the feeling was mutual. This perfunctory dual biography of the actors typecast forever after as ''Fred and Ethel'' offers a glimpse of their unsung real lives: he, a veteran vaudevillian and bachelor drunk; she, a Broadway belter with a history of emotional troubles. But the writing is sloppy, and at times there's entirely too much information -- do we really need to know their social security numbers? C+