This is a very nice book on group coaching and team building. In my opinion, it is not so much about Scrum or XP methodology: the reader is supposed to already be familiar with the agile approach (applied to software development or otherwise). The coach is described in his/her many faceted role: mentor, facilitator, teacher, problem solver, conflict navigator, collaboration conductor... However, the key takeaway, for me, is that an agile coach and a leader is someone who allows the teams to unfold these qualities for themselves. Thus, the leader makes the team, like the sea makes the land, by gently drawing back.

I loved the reference to the Shanghai Quartet, by the way!