Well, the introductory section implies that the author (a) knows Walker's aim in his book, (b) receives direct emails about the book, (c) "very much appreciates" learning about errors in the book, and (d) knows what is planned in future editions of the book. The author's name is "sleepdiplomat"—it's odd that he doesn't explicitly give his name—but it turns out that (1) sleepdiplomat.com claims to be Matthew Walker's web site, and (2) @sleepdiplomat appears to be Walker's Twitter handle. Either someone has faked up an entire online presence for Walker, or the Wordpress post is indeed Walker himself.
