Note: The book Create an Oasis with Greywater is required in order to effectively use the "Builder's Greywater Guide".
Art Ludwig has cut to the core of wastewater issues. He's obviously done all of his homework, mulled-over the variables, and come up with a common sense, economically reasonable, environmentally responsible approach to wastewater. I expect to save money that I would have spent on a post-septic tank, aerobic unit that would seemingly have been ecologically responsible; but because of the technological overkill, ultimately that system would have defeated my altruistic environmental concerns.
The sheer volume of information in each of his greywater books puts other sources to shame. Each volume is very well written, being clear, amusing, and concise. I can't imagine improving these books, other than keeping the information updated with future editions.
These books talk the talk and walk the walk better than anything else that I've seen. Buy a set for yourself, a set for your neighbors, and a set for the regulators.