Black letter law is implemented in countless shades of gray, with interpretation and negotiation at virtually every step of the way. Prof. Dave Owen’s The Negotiable Implementation of Environmental Law digs deep, beyond the obvious, to underscore that negotiation is not a dark art but a necessary skill that deserves more attention and training. He catalogs the importance, prevalence, and pitfalls of negotiation, providing examples of what is negotiable, when and by whom, how it happens and what results, and whether it can be good or bad on the scale of rigid “command and control” versus flimsy “slippage.” Professor Owen’s analysis is thorough and balanced on the “centrality of negotiation” and how it impacts outcomes in the world of standards, permits, cleanup, conservation, and enforcement. He also underscores the value of and need for improving the transparency, effectiveness, and equity of negotiation, particularly in state agencies.