This book is devoted to the PDP-11 computer, manufactured by the Digital Equipment Corporation. Computer programming is a practical art that is to be bolstered by theoretical wisdom but developed as a skill by continual practice. The approach of this book is that the reader will be writing complete programs (albeit rather trivial ones) at the earliest possible stage. There are no prerequisites, no prior experience with or theoretical knowledge of computers. The text can be used by beginning or advanced PDP-11 users. Beginning with encoding a great variety of small, individual tasks which are then utilized in building larger, complete programs using these individual blocks, or modules.