I should note Herrin was an advocate of air dried wood and opposed to kiln dried wood. It should be noted that the concept that kiln dried wood is somehow inferior to air dried wood is actually just an urban myth. If you read chapter two of Volume Two of The Traditional Bowyer's Bible you will understand why it is an urban myth that kiln dried is inferior. (The reason is due to amateur bowmakers using kiln dried wood and breaking the bow during the tillering process - and then blaming the wood, when in reality the error was with the beginner bowyer who was clueless about how to make a bow. In scientific testing kiln dried wood is actually superior to air dried wood when it comes to bow making.)
Ignoring Al Herrin's perpetuating the urban myth, the video below is very handy for people looking to get into bow making. I also strongly recommend that people purchase The Traditional Bowyer's Bible volumes 1, 2, 3 and 4. Volume 1 is basically mandatory, but the other volumes are also extremely useful.