For preteen and young teen boys: a clear, easygoing explanation of the changes accompanying sexual development. As she did in her like-titled work for girls, Madaras treats the mechanics as just a small aspect of sexuality; in a separate section, she briefly discusses the specific concerns of this age. Madaras covers physical matters in detail, step-by-step through the changes of puberty; she includes a chapter on girls-and-puberty that will help readers understand what is going on with the other sex. This is all done in Madaras' forthright style: her young male co-author, and her own experience teaching classes in sex education, have kept her on-target in speaking to readers' worries and wonderings. In an introduction to parents, Madaras suggests that the book be read separately and together, and offers sage advice on broaching difficult subjects (""What do you say? 'Hi, son, been masturbating lately?'""). Older boys will do better with Jay Gale's A Young Man's Guide to Sex (p. 477) for a fuller discussion of other than physical matters; for the younger crowd, and for starters, this is fine.