Late in 2012 I reviewed Greek GM Efstratios Grivas's Chess Analytics, a good and solid work aimed at strong and ambitious players - 2000+ in my opinion. There was some controversy around the book as one section clearly reproduced Lubomir Kavalek's analysis of and commentary on a particular ending, and did so without citation or permission. There was a huge hullabaloo about this which is not worth rehashing; I'll simply offer the conclusions I've drawn from seeing Kavalek's and Grivas's pieces on the ending in question and from Kavalek's and Grivas's discussions of the plagiarism charge:
1. Objectively, Kavalek's material was plagiarized. It's just about impossible to deny it, and Grivas acknowledged that he made the mistake.
2. Culpability: Grivas asserts (in a letter he sent to various sources that did not publish it, and then to me much more recently) that it was an accident and not intentional. As he is certainly a strong enough player to produce a competent analysis of that ending and as there are no other controversies around the book (of which the particular ending constitutes a very small part) it seems reasonable to give Grivas the benefit of the doubt in the bigger picture. That doesn't mean that plagiarism is okay. The point is more modest: there's good reason to take him at his word and accept that it was an accident.
In the comments to that earlier post, however, other alleged instances of plagiarism are alluded to. Via email, Grivas has offered a reply (to at least one of the charges), which I've also posted in the comments to the original piece:
On the other case on my 2003 book (my God, it is already 10 years with this crap!) which is mentioned in the comments: it was contracted with the Greek Chess Federation and it was clear from the first moment that this will be a collection of material for a training program of the federation – not any original work at all. 2/3 of the book was translated material and 1/3 was coming from older books of mine – nothing new under the sun, as the bibliography of the book can justify. The entire negative story is created by Mr. Ilias Kourkounakis and his (opposition to the federation) friends who love to fight me (I support the federation’s Board) and the Greek federation.
It is to allow Mr. Grivas to reply to the charge in the comments that this post was written; the dispute with Kavalek is off the table for discussion from all parties. If Mssrs. Kourkounakis and Grivas wish to discuss the matter here, they may do so (preferably briefly and with civility); otherwise I would prefer that these rather fetid discussions end with this.