I first read the first edition when I began working with teams over 10 years ago, and I found it highly valuable. Returning to it years later, I made new insights. Now, with the release of the second edition, I'm reminded of the core concepts but also discovering new approaches.
In the second edition, the have increased their level of codification, making it an excellent resources suitable for managers, team members, scrum masters, and team coaches of varied seniority levels.
One thing I particularly like about the second edition, is that this book, much like "Teamwork Is an Individual Skill" by Christopher Avery, can be read by team members and offers them a better understanding of how they can contribute better to team improvement.
As a general summary, I think the second edition picks up where the first left off, and now offers a deeper dive into the structure and theory of retrospectives while also providing more practical stories and hands-on instructions. Esther, Diana, and David excellently codifies how to establish or restore evolutionary capabilities in teams, addressing naturally occurring group dynamics, goal achievement, collaboration, and more. The second edition also covers strategies for dealing with issues arising both within and outside the team, including those related to individual team members.
I think this book offers great leadership development, and is a must read for anyone working with teams.