Thanks for the tips. he's working with a coach over the internet who has suggested the opening. My friend has got the King DVD and was asking me about a book. I've told, as may seem obvious to ask the coach ! I know normally the coach has aimed to get a consistent type of position into my friend's game. I was a little surprised when the Najdorf was mentioned but I guess something other than the Poisoned Pawn and maybe the ..., e5 tack in general may fit the bill. There seems to be a lot of talk about the Doknjas book, as Jonathan mentions and the sample is interesting.

Yes indeed, but I don't know a of better source for the ...e6 lines. The Najdorf is a big beast and a prospective player won't necessarily find everything they would like in one book.

I would recommend a decent strength player to think about a couple of questions before choosing a book. Firstly, against 6.Be3 and 6.Be2, do you want to play setups based on ...e6 or ...e5? Secondly, against 6.Bg5, do you want to play a poisoned pawn variation or not?

If you know the answers to these questions, just get a recent book that most closely matches your intentions. For example, the brothers Doknjas go for ...e5 setups in general (but 6.h3 e6, apparently), and 6.Bg5 Nbd7; Pavlovic also goes for ...e5 setups, and 6.Bg5 e6 7. f4 h6 8.Bh4 Qb6. I you want to play Scheveningen setups with ...e6, Lorin D'Costa's The Sicilian Scheveningen Move by Move is the one to go for. (Lorin uses the move order 1.e4 c5 2.Nf3 e6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 d6 and then 6...a6 unless a different sixth move is preferable.)

If you don't yet know the answers to these questions, you're going to need to look at more than one book. I would start with The Sharpest Sicilian by Georgiev and Kolev (Chess Stars), as the authors are strong players and their explanations are good. Or, of course, look through lots of annotated games on ChessPub!