This book provides a superb introduction to and overview of the MIT PI System for custom VLSI placement and routing. Alan SherΒ man has done an excellent job of collecting and clearly presenting material that was previously available only in various theses, conferΒ ence papers, and memoranda. He has provided here a balanced and comprehensive presentation of the key ideas and techniques used in PI, discussing part of his own Ph. D. work (primarily on the placeΒ ment problem) in the context of the overall design of PI and the contributions of the many other PI team members. I began the PI Project in 1981 after learning first-hand how difΒ ficult it is to manually place modules and route interconnections in a custom VLSI chip. In 1980 Adi Shamir, Leonard Adleman, and I designed a custom VLSI chip for performing RSA encrypΒ tion/decryption [226]. I became fascinated with the combinatorial and algorithmic questions arising in placement and routing, and beΒ gan active research in these areas. The PI Project was started in the belief that many of the most interesting research issues would arise during an actual implementation effort, and secondarily in the hope that a practically useful tool might result. The belief was well-founded, but I had underestimated the difficulty of building a large easily-used software tool for a complex domain; the PI softΒ ware should be considered as a prototype implementation validating the design choices made.