The following is a list of books taking almost directly from Amazon.com. I'll group them into poly-specific, poly-related, and poly-friendly. Not all of them talk entirely about polyamory or even responsible non-monogamy, but they'll touch on the subjects. I also have a category (Good Information) for books that focus on topics that transcend just poly but apply to all relationships.
Poly-Specific: books that talk very specifically about polyamory or non-monogamy.
"Opening Up: Creating and Sustaining Open Relationships" by Tristan Taormino
"Polyamory: The New Love Without Limits" by Deborah M. Anapol
"Polyamory: Roadmaps for the Clueless & Hopeful" by Anthony Ravenscroft
"Pagan Polyamory: Becoming a Tribe of Hearts" by Raven Kaldera
"Spiritual Polyamory " by Mystic Life
Poly-Related: books that have sections related to poly, but also talk about a number of other topics.
"The Lesbian Polyamory Reader: Open Relationships, Non-Monogamy, and Casual Sex" by Marcia Munson (Author), Judith Stelboum (Editor)
"Polyamory Many Loves: The Poly-Tantric Lovestyle: A personal account" by Janet Kira Lessin
"Boundless Love: I Love You Two" by Jarod Lojeck (Author), Michelle Devon (Editor)
Poly-Friendly: books that mention polyamory or non-monogamy as an option in the topics discussed in the book.
"The Ethical Slut: A Guide to Infinite Sexual Possibilities" by Dossie Easton and Catherine A. Liszt
"The Sex and Love Handbook: Polyamory! Bisexuality! Swingers! Spirituality! (& even) Monogamy! A Practical Optimistic Relationship Guide" by Kris A. Heinlein and Rozz M. Heinlein
Don't let the names fool you; this isn't another "Stranger in a Strange Land" book.
"Marriage, a History: How Love Conquered Marriage" by Stephanie Coontz
"My Husband Betty: Love, Sex, and Life with a Crossdresser" by Helen Boyd
"Plural Loves: Designs For Bi And Poly Living" by Serena Anderlini-D'Onofrio (Editor)
"Eros: A Journey of Multiple Loves" by Serena Anderlini-D'Onofrio
Good Information: books about everything from jealousy to casual sex.
"The Dangerous Passion: Why Jealousy Is As Necessary As Love and Sex" by David M. Buss