Babyhood

If you don't already tune in to Mad About You, but absolutely must know what Paul Reiser thinks about babies (his real-life son, Ezra Samuel, is a toddler), then pick up this book. Reiser's follow-up to 1995's best-selling Couplehood is an innocuous collection of aimless anecdotes and observational shtick, most of which will more than likely turn up this fall on Mad, where, coincidentally, his character became a first-time father last May. Besides a few straightforward notes about the downside of parenting, Babyhood is packed with setup-punchline zingers (''People often ask me, 'What's the difference between couplehood and babyhood?' In a word? Moisture'') that will probably sit better on a sitcom than a bookshelf. C+