This book is about the C++ programming language and how to use it to write abstract data types and object-oriented programs. An abstract data type is a programmer-defined data type that encompasses data elements along with the operations that can be perfomed on them. Object-oriented programming (O-OP) extends the concept by organizing abstract data types and exploiting their common features to reduce programming effort. This book grew out of a project, on which the authors continue to work at the time of this writing, to make UNIX-based workstations more useful to biomedical scientists at the National Institutes of Health (NIH).