Well, what a controversial topic this is! In “reverse order” what is incontrovertible is that Patrick Matthew (PM) espoused the theory of Natural Selection in Naval Timber & Arboriculture (NTA) decades before Darwin and that Darwin acknowledged this in a letter to PM dated 13th June 1862: “I presume I have the pleasure of addressing the author of the work on Naval Architecture and the first enunciator of the theory of Natural Selection”. I have seen and touched this letter, the actual letter, as it is held in the National Library Scotland.
Now, did Darwin know about PM's writings in NTA? Unlike the letter cited above there is no absolute proof of existence of documentary evidence. However Sutton provides a substantive case with numerous examples of likely routes to Darwin knowing of content. Sutton principally uses computerised methodologies to compare word patterns and phrases in texts to “mine” for this evidence. You may or may not be convinced - but, as another reviewer has said, on the balance of probabilities it would seem likely that Darwin was indeed aware.
If you are reading this then you must be interested in the topic so why not read the book (which admittedly could do with a good “edit”) and judge for yourself.
I would also like to add that I'm surprised at the virulence of, I assume, the “pro Darwin “ lobby protesters here and elsewhere. It is perfectly reasonable for Sutton to argue his case. Why the need for obnoxious comment? I smell a rat ! - desperation to support the unsupportable?
The world needs challengers like Sutton – good luck to him I say.