This book is reminiscent of junk mail that entices a reader to buy more based upon repetitive success stories and promises to show the secrets that 'they' don't want you to know. Each spurious rule (eg. 'brand yourself', 'build your confidence') is represented by a different author who writes around 300-400 words illustrating in the most indirect way possible the result of what happened when they followed the extraordinarily-vague rule, while also plugging their website or product.
I think my favorite is rule #19 - "Get a Ph.D." - which, apart from being irrelevant to driving success with books, fails to mention a Ph.D. at all in the subsequent explanation. "Books, if they're useful, informative, and well written, encourage people to send work to you," enthuses Shel Horowitz in a blinding example of the obvious. "When you have a book, you pretty much have automatic access to (and exposure on) high-traffic websites such as Amazon.com and Google.com," he continues, failing to mention that this has no bearing on your own website unless the book is popular, and has nothing to do with how SEO actually works.
As a 140 page book, 40 pages are dedicated to the photographs and bios of each author, together with an invitation to write your own 42 rules book, and the catalog of other books available. Take away the introduction and table of contents, and this is a very, very thin read which offers absolutely no substantive information to prospective authors. I agree with the other review entitled "No Value" - I haven't quite figured out if this is a pyramid scheme or some other type of marketing game, but I'd strongly advise against wasting $20 on this. There are many other reputable books written about how to write and get published which aren't assisted by questionable 5-star reviews.