An exemplary science activity book, giving instructions for building six types of wheel machines. Lucid directions for constructing models of the pulley, windlass, gear, water wheel, windmill, and paddle wheel are interspersed with brief notes on the historical importance of each invention. The models get progressively more complicated, making this useful for a wide range of ages and expertise. Throughout, the young investigator is encouraged to explore and question the capability of each model; once the machine is completed, ""More Experiments"" offers options for further learning. At the ends of chapters, ""What's Happening"" summarizes the principles of physics that are used, while still allowing readers to draw their own conclusions. Doty's accompanying illustrations achieve an excellent blend of clarity and humor, and most important, the wealth of information is presented in an appealing manner. All of the materials used are readily accessible. One minor concern: some of the constructions are tricky, others fragile, but Zubrowski gives fair warning on these points and presumably has tested the models himself. If they can get the wheels to hold together, this should prove to be a most valuable resource for both young experimenters and their teachers.