Announcing the new title in the P-II Junior Research series: The essentials of scientific inquiry are outlined and discussed -- Observation, Hypothesis, Experiment, Theory and Proof. A very practical problem leads up to this and involves all the steps as a young boy learns to feed a small pup. The chapters that follow describe the experiments of eight scientists, progressing from Galileo to Fermi, always emphasizing the scientific method as they applied it. The black and white illustrations provide a reasonable likeness of the scientists at the start of each chapter. Since these carry no other information, photographs and reproduced portraits would have been better.