Mark Sisson is an American fitness author and blogger, and a former distance runner, triathlete and Ironman competitor. He has written several books, including The Primal Blueprint, which is a classic. Mark Sisson’s website, MarksDailyApple.com, is one of the most viewed websites for Paleolithic-type lifestyle. Mark is also the creator of the Primal BluePrint Expert Certification program. In my opinion, his books and blogs are the most thoroughly researched sources for accurate primal information. I was honored to be interviewed for his podcast, The Primal BluePrint Podcast. Here is the link to that podcast.