In a sequel to the ever-popular My Side of the Mountain (1959), 15-year-old Sam Gribley's feisty sister Alice, 13, has joined Sam's self-sufficient existence in the Catskill wilds. Alice has her own quarters in a rabbit-skin-insulated treehouse, and even Sam has built himself more comfortable furniture; but Sam is more persistent in living an unmechanized existence than Alice, who introduces a plumping mill to grind their acorns and even hopes to generate electricity. The minimal plot here involves the kidnapping of Sam's beloved peregrine falcon by a man posing as a conservation officer accusing Sam of illegally harboring an endangered species. George uses rather elaborate devices in Sam's narration of what is as much Alice's story as his, although she is almost always offstage: flashbacks set the scene with Alice's arrival, while her dauntless quest for the miscreants and her adventures along the way, which are arguably the book's most interesting events, are narrated entirely from Sam's point of view as he follows clues that she has deliberately left for him. George has outdone herself on authentic details of living from the land: the story here is so weighed down by its informational component that it is almost more a handbook than a novel. Still, it's an excellent handbook; and for readers persistent enough, or interested enough, to stick with it, there are several colorful characters and an intriguing puzzle to follow to its satisfying conclusion.