I don't think there is a single book that you could call "definitive" or "best in field".   Weissman's book is good, but it is just one insiders view and I think needs some perspective.

I really like Ronald Cohen's book "Rainbow Quest". I thought it covered more territory and gave a better view of what was happening all across the country during the revival. There were various regional pockets of activity that produced distinct "sounds" and styles.   I think Cohen also gave a bit more insight on the political aspects of the early days of the revival and the "conservative" politics that were involved before "folk music" became more associated with the left.