I loved HIT. I think it's just about one of the best books available. It's written from a camp of guys who were once just school kids themselves out running fartleks and it shows how guys (and girls) like them became good. Primarily, by doing a lot of aerobic running. We all know this is a key ingredient, but most books talk about so many aspects of running that the simple focus on doing a lot of running gets lost in the noise. This books is concise and mostly focused on aerobic running, so the importance isn't lost on the reader. It's one of the few books where 90% of what we should be running comes close to taking up that percentage of the pages in the book. I think most other books by the end make it easy for a runner to have some kind of denial, as if including all the ingredients to good running can short cut them to success. When you finish HIT you understand that to be good you still need to put in serious aerobic volume.
I could have done without the parts about being a chiropractor; that seemed very self-serving for the author. Some of the other chapters lose focus a bit. All-in-all it's a great book, though, as it clearly breaks down the relevance of aerobic running and how it fits into a system of training.