In their irrepressibly direct way, the Dworkins answer the questions most frequently asked by their N.Y.C. radio and TV audiences. The specific house plant questions are grouped by family, which makes the Index essential, but there are smaller sections on bugs, compost and feeding, humidity, light, plus assorted odds and ends. One misses the mutual interruptions that personalize their on-the-air delivery, but the advice is streamlined and laced with colloquialisms (""Hang loose"") and offhand humor (""if the spines don't get you, you'll probably love it""). Obligatory pot stop for ailing ferns and drooping Dracena.