A Cooperative Method of Natural Birth Control

This book teaches a natural method of birth control including a chart which one can use for each month. The process is said to be very effective and is explained clearly in the book. Although this information provided is a Calendar-based method and tracking of fertility/infertility during ovulation, it is not the rhythm method. It's the combination method of keeping track of monthly cycles, counting days of possible fertility, cervical mucous testing, and basal temperature tracking. It's a great method and it works.