After several years of searching, I finally found a good hardback copy of this book, and took it with me to read on a plane trip to Austin Wednesday, almost finishing it in a day. Very good book, and helped explain a lot of things about the HBO miniseries that weren't clear to a civilian (unit organization, for example). Ambrose writes well, but this is an unusual book in that it is really a first-person narrative by Ambrose of his experience interviewing the veterans, narrating their stories for the most part, but at times commenting on the interviews or adding tidbits he learned while working as Eisenhower's biographer.
Very good book, though, and the HBO series does it justice.