If, like us, you have two left thumbs, no bicycle repair guide will suddenly transform you into a superhandyperson -- this applies to the ladies too -- capable of truing the rim of that wobbly wheel or making even simple gear adjustments. But if any how-to book can turn a mechanical idiot into a competent bike mechanic, it's Al Carrell's -- as direct and easy to follow a manual as you'll find on the market today (compare, for instance, Alth's bewildering All About Bikes and Bicycling, KR, 1972, p. 753). Following a checklist of essential tools, Carrell provides A-B-C directions for everything from straightening a bum spoke, changing a flat tire, and fixing the brake hand lever to confronting a broken chain or bent sprocket with at least a modicum of confidence. There are also chapters on accessories, special bikes, and security and hauling. So rest easy, freewheeler -- here's everything you always dreamed could go wrong, but can now handle. . . bar none.