There are many good sources of astrology books. Here are just a few.
American Federation of Astrologers (AFA)
The American Federation of Astrologers has an extensive list of books available on astrology. Included in the more than 1,000 titles available from AFA are numerous translations by Robert Hand, James Holden and others with expertise in traditional astrology. The AFA is the official distributor for ARHAT Media Ltd.