For the thoughtful and scientifically curious gardener, not the housewife with a green thumb and a pot of begonias on the windowsill, Langer (The After-Dinner Gardening Book) explains all the basic processes of plant growth and care in a disarmingly informal, winning way. The environment of the average city apartment is, let's face it, hostile to plants; Langer however is an ingenious improviser: he uses a chinning bar from the sporting goods store for hanging plants from window frames that otherwise couldn't support the weight. He informs you that plants in hanging baskets need to be watered and misted more often (hot air rises). And for the serious plantgrower he goes through the pluses and minuses of various artificial lights -- fluorescent, incandescent and special plant ""grow"" lights. As to what you should cultivate, Langer has a section on ""low-light specials"" for beginners whose windows overlook an airshaft, one on the hardier cacti and succulents, another on ferns, ""the most primitive of all houseplants."" And Finally onto roses, orchids, bamboos and other challenges to indoor ecology. Langer uses his own misadventures as a touchstone and what with a three-year-old daughter and constant horticultural experimenting you tend to trust his advice. He seems to have come by his wisdom the hard way.