When I first started working on The Joy of Clojure a sub-goal (aside from even completing it) was to create something that was useful and unique across different editions. This was motivated by the fantastic "Modern Operating Systems" by Tannenbaum. amazon.com/Modern-Operati…
Each edition covers the latest in OSDev tech but it also frames examples in slightly different example Ones, modern and historical. The case studies cover differing sets across different editions and the research sections in older editions typically feed the focus of later eds.
On top of all of that, the bibliographies act as fascinating snapshots of OSDev theory over time.
Truly it's worthwhile to read every edition of Modern Operating Systems and I hope that with JoC the same could be said of the 1st and 2nd editions.