Jack Marrion's 'A Suitable Approach' is still my favorite but it's out of print. Sheryl's Moore's new book is also incredible.First learn what they are, then learn what they do. After that, you can start shopping for companies.
Quite a few books to help you get started:
https://www.amazon.com/Taxation-Suitability-Annuities-Professional-Advisor/dp/B086PV22R6/
[EXTERNAL LINK] - Amazon.com
[EXTERNAL LINK] - Amazon.com