Another installment in the whimsical boyhood of Kraft's alter ego, Peter Leroy, following this year's Little Follies, a gathering of all the adventures to date. Peter embarks on the great world of the seventh grade, in which he encounters a science teacher, Miss Rheingold, the most beautiful woman in the world. Miss Rheingold does not so much want her students to learn science as to ``fall in love with it,'' and Peter does, or at least he falls in love with Miss Rheingold. She divides the class into groups and assigns a paper with no deadline. The theme is, ``Where does it stop?'' and the question bedevils Peter into adulthood. Where, in fact, does childhood end and adulthood begin, or what are the precise boundaries of love, or when do we begin to die? Kraft's writing is subtle, on a par with the early Vonnegut for its playfulness with graphs and ultimate scientific questions, as innocent as Booth Tarkington's Penrod in its boyish maneuverings. The seventh grade is also where Peter learns about black children, how the world does not stop with the boundaries of his prosperous Long Island suburb, how it doesn't stop, either, with the poverty now a part of his expanded consciousness. Kraft's humor is always grounded in common, rather sad truths; only occasionally does he overextend his jokes, as with Peter's worry that he has somehow violated essential rules when he doesn't follow instructions on first opening a new textbook. In the end, Kraft's entire novel is Miss Rheingold's paper, turned in many years late, but in profound tribute to her wisdom. The best entry so far in an engaging series.