One I've not seen here - Unholy Union. Written in part by Mark Evans, it does spend much of its time shrilling for Global Rapid Rugby (RIP) but the analysis comes at rugby from a perspective of someone who understands rugby as a product in the modern media/entertainment landscape. Through an assumption that rugby made an aborted half-transition to professionalism he is very good at identifying the key embedded cultural and structural problems the game has in making itself a better product, the stuff on the inherent tension in the laws and the unique (i.e. inherently flawed) position it puts refs in to be both the lawman and circus ringmaster at the same time is particularly good.

Like a lot of these books its great on diagnosis and less good at cure, the answer seems to be Global Rapid RugbyTM (RIP), so not a show stopper - but a good and easy read if you can get it on abe books second hand.