This maybe a bit off-topic but I fail to understand why the top 2 textbooks on Distributed Computing - Tanenbaum and Coulouris - don't have a dedicated section

This maybe a bit off-topic but I fail to understand why the top 2 textbooks on Distributed Computing - Tanenbaum and Coulouris - don't have a dedicated section on Consensus Algorithms. I learned distributed computing from Tanenbaum and can't recall encountering it. Contrary some of the folks here, I found the presentation very cool. But that maybe because I'm a slow learner.