We would like to thank the many individuals who helped review the chapters and provide some of the photos used in this book. Peter Norbeck and John Metesh of the Montana Bureau of Mines and Geology in Butte, Montana, provided several helpful comments on some of the chapters. Dr. Mark Sholes and Dr. Hugh Dresser from the Department of Geological Engineering at Montana Tech of the University of Montana provided helpful suggestions on Chapter 2. Dr. Dresser provided all of the stereo pairs found in the book. Dr. Chris Gammons, who took John Sonderegger's place in helping direct the Montana Tech Hydrogeology Field Camp since 1997, provided many helpful comments for several of the chapters, and his help has been invaluable. Dr. William "Bill" Woessner was instrumental in providing significant help in Chapter 6 and in providing some of the photos. Dr. Woessner teaches a week of our hydrogeology field camp. Dr. Peter Huntoon provided some of the photos for Chapter 2 as well as helpful encouragement and examples. Dan O'Keefe, of O'Keefe Drilling in Butte, Montana, was very helpful in reviewing the drilling section and provided photos for Chapter 8. Kevin Mellot was very helpful in scanning the many slides used in the figures. We wish to thank our many students over the years for being the subjects of photos and providing good questions and discussion and the cooperating specialists, especially Herb and Dave Potts, Dan O'Keefe, Fred Schmidt, and Hayden Fergeson. Bob Bergantino of the Montana Bureau of...