While Dave Gaughran may be an acquired taste - he's Irish and proud of it - the information he provides in Strangers to Superfans appears solid, logical, and verifiable. In other words: it's worth buying and reading the book whether you like his style or not.
I happen to like his style, even though he gets a bit overboard with the asides from time to time to time to time.
The book is divided into five sections.
The first is devoted to finding your ideal reader and to granular targeting - what it means and why you should target your 'ideal reader'.
The second, third, and fourth analyze your ideal reader's journey from finding the book to voluntarily buying and reviewing it. I found the statistics on this process enlightening and horrifying. Did you know that more than half your purchasers won't finish the book, let alone review it? Chew on that a while.
The fifth is a catch-all and summary telling you how to relaunch a book and why you should start with a re-editing rather than at the other end - with a new cover and blurb.
Gaughran's thesis is that (1) we're dealing with Buyers, and (2) they go through five phases in order to become what you really want them to be: People who Love You & Your Book So Much, that they will RECOMMEND YOUR BOOK to their FRIENDS.
Nobody does this lightly: when has a friend recommended a book highly and you thought it stank. Did you trust them again? It takes a while to rebuild that trust, assuming you ever do.
"But I want to know how to Sell my book," you complain. "All I need to do is learn to write a little better. I'll take a workshop."
Wonderful. Do that, but if you want to know why it doesn't sell, buy his bloody book and read it.