This book describes the implementation of Icon in detail. It received uniformly good reviews, with comments such as "a classic" and "a fascinating read". Highlights include:
* Icon's virtual machine
* the interpreter for the virtual machine
* generators and goal-directed evaluation
* data representation
* string manipulation
* structures
* memory management
The book describes the implementation of Version 6 of Icon. Most of the material in the book still is relevant. Two technical reports supplement the book to describe subsequent changes. The implementation of Icon's graphics facilities is not described.