This textbook is one of a series of publications designed to provide information needed by Navy personnel whose duties require an elementary and general knowledge of the fundamental concepts of number systems, logic circuits, and Boolean algebra. Topic 1, Number Systems, describes the radix; the positional notation; the decimal, binary, octal, and hexadecimal number systems; and the conversion techniques needed to convert from one system to another. Topic 2, Boolean Algebra, includes rules, laws, mechanization, and simplification techniques. Topic 3, Logic Circuits, includes logic computation; logic polarity; and the six basic logic circuits of AND, OR, NOT, NAND, NOR, and Exclusive OR. A glossary of terms is included. (MNS)