The purpose of this work is to present the most pertinent parts of the body of physics knowledge which has been built up in the course of the Naval and Shippingport (PWR) Reactor Programs, with the aim of providing a background of understanding for those interested in nuclear core design. Volume 1 of this handbook was planned to bring together topics in the basic theoretical and experimental material which are of especially wide interest, including those common to both thermal and intermediate neutron energy reactor types. The physics design of light water-moderated and -cooled reactors is covered in Volume 2 (classified), and that of intermediate neutron-energy power reactors in Volume 3. The emphasis in Volume 1 is thus on light water reactor systems, and as many recent advances in reactor physics of the Naval and Shippingport Reactor Programs as possible have been included.