This is an excellent resource, as both and introduction and a how-to guide, on polyamory (or ethical non-monogamy). The authors give an honest, no-nonsense approach that stresses compassion and personal integrity. There are useful chapters on understanding what polyamory is (and how it differs from and sometimes intersects with swinging or bdsm), better communication skills, potential pitfalls, coming out, safer sex, and more, all interspersed with personal anecdotes from the authors and many others.
I'd honestly recommend this to everyone, if only for the communication skills they teach! I also enjoyed the introspective questions they share at the end of each chapter. It's a bit dry in the beginning, at least for me, but overall it was a really great read.