help me to understand cams

I've been messing around with these things for over 30 years and yes I too am still learning.
There is a book that I have bought just recently by a guy by the name of David Vizard. The book "how to build horsepower" has a complete chapter (and more) just on cam function and theory. Some of my long held beliefs on cam selection have now been changed due to the information revealed in this book. If you can set up the overlap to work with a scavenging of the exhaust setup, you can reap great advantages in efficiency and power. I recommend the book for gaining knowledge in cam theory.