John F. Kippley

Using the temperature method to determine fertility, this book offers couples another option for planning for conception and birth of children.

No, you don't need chemicals or barrier methods. It's as effective as the pill (this is NOT the rythmn method) and in most cases doesn't require excessive abstinence. And it actually helps you monitor your own health. Main problem: no on-going money-stream from selling pills or devices, so no one markets it.

A solid overview of NFP (Natural Family Planning). Lots of detail and great information, if a bit dry at points. The standard NFP practical reader.