I’m a new member here, but I wanted to put in my $0.02 about NFP.
My husband and I took a local Catholic Charities class on CM-BBT (cervical mucus-basal body temperature) over 10 years ago and it was one of the best decisions we ever made. The fee was nominal, and it was a wonderful start to learning about NFP.
However, I came across a book shortly after taking the CC class that has proved to be invaluable. In fact, after reading the book, I would not have had to take the CC class. The name of the book is Your Fertility Signals by Merryl Winstein. It is the most succinct book on NFP that I have found. Its format is simple, easy to understand, and covers mucus, temperature, and cervical positioning completely. In addition, the book covers topics like breastfeeding (and how it impacts your fertility signals) and infertility self-help. It also shows you a way to naturally determine pregnancy even before a store-bought pregnancy test can tell you (it works, too–it successfully confirmed my pregnancies with my 2 children before it even registered on the ept test!). The book also provides a helpful list of teachers if you still feel that you need one, plus a list of sources for further reading. It is only 160 pages and is chock full of useful information. I refer back to it many times. I highly recommend it!
I HAVE THAT BOOK TOO! I HAVE BEEN USING IT FOR THREE YEARS NOW! I LIKE IT A LOT