by Kurt Keutzer Those looking for a quick overview of the book should fast-forward to the Introduction in Chapter 1. What follows is a personal account of the creation of this book. The challenge from Earl Killian, formerly an architect of the MIPS processors and at that time Chief Architect at Tensilica, was to explain the significant performance gap between ASICs and custom circuits designed in the same process generation. The relevance of the challenge was amplified shortly thereafter by Andy Bechtolsheim, founder of Sun Microsystems and ubiquitous investor in the EDA industry. At a dinner talk at the 1999 International Symposium on Physical Design, Andy stated that the greatest near-term opportunity in CAD was to develop tools to bring the performance of ASIC circuits closer to that of custom designs. There seemed to be some synchronicity that two individuals so different in concern and character would be pre-occupied with the same problem. Intrigued by Earl and Andy's comments, the game was afoot. Earl Killian and other veterans of microprocessor design were helpful with clues as to the sources of the performance discrepancy: layout, circuit design, clocking methodology, and dynamic logic. I soon realized that I needed help in tracking down clues. Only at a wonderful institution like the University of California at Berkeley could I so easily commandeer an ab- bodied graduate student like David Chinnery with a knowledge of architecture, circuits, computer-aided design and algorithms.