Bill Keel, the author of The Road to Galaxy Formation (Springer-Praxis 2002), has been involved in many areas of extragalactic astronomy, and for the last 18 years has worked at the University of Alabama. Of particular relevance to this book is his study of gravitational lensing since 1980, early calculations on microlensing of quasars, and an ongoing Hubble survey for gravitational lensing effects in silhouetted galaxies as a constraint on massive dark-matter candidates. His experience in serving on 16 NASA review committees for various space-astrophysics missions and higher-level programmati...