Acknowledgments The technical and operational information contained in this Handbook is the summary of the experience gained by members of the STScI ACS-WFPC2 Team (AWT), the ACS group at ST-ECF, and by the ACS IDT. Members of the STScI ACS-WFPC2 Team are Marco Sirianni (lead, ESA), Luigi Bedin (ESA), John Biretta, Francesca Boffi, Ralph Bohlin, Marco Chiaberge (ESA), Colin Cox, Daiana Dinino, Van Dixon (JHU), Andrew Fruchter, Ron Gilliland, David Golimowski (JHU), Shireen Gonzaga, Anton Koekemoer, Ray Lucas, Jennifer Mack, Matt McMaster, Max Mutchler, Cheryl Pavlovsky, Vera Platais, Charles Proffitt, Kailash Sahu, Linda Smith (ESA), Deepashri Thatte, and Nolan Walborn. The ST-ECF ACS group is Martin Kuemmel, Harald Kuntschner, and Jeremy Walsh. The ACS IDT is Holland Ford (PI), Garth Illingworth (Deputy PI), George Hartig, Mark Rafal, Frank Bartko, Tom Broadhurst, Bob Brown, Chris Burrows, Ed Cheng, Mark Clampin, Jim Crocker, Paul Feldman, Marijn Franx, David Golimowski, Randy Kimble, John Krist, Tom La Jeunesse, Mike Lesser, Doug Leviton, George Miley, Marc Postman, Piero Rosati, Bill Sparks, Pam Sullivan, Zlatan Tsvetanov, Paul Volmer, Rick White, Bob Woodruff, David Ardila, Narciso Benitez, John Blakeslee, Rychard Bouwens, Larry Bradley, Nicholas J.G. Cross, Ricardo Demarco, Tomotsugu Goto, Caryl Gronwall, Brad Holden, Nicole Homeier, André Martel, Simona Mei, Felipe Menanteau, Gerhardt Meurer, Veronica Motta, Marco Sirianni, and Hien Tran. The contributions of Ilana Dashevski, Warren Hack, Alan Welty, Tom Wheeler, and Susan Rose are greatly appreciated. ix x Acknowledgments