This book is intended to serve as an introduction to C3 systems and technology. It is roughly structured to address three topics: C3 hardware, C3 system organization and design, and C3 system development and application. Although primarily concerned with electronic engineering issues, it deals also with human-computer interfaces, other human performance and organizational factors, and modeling. Each of the twelve chapters concludes with an exercise on the material presented therein, and the book concludes with two appendices (one on the properties of communications channels and the other on systems tools) and alist of (primarily electronic engineering) references.