Good morning...

I would like to understand better about the difference between an openings book that is suitable for human play compared to a book that is designed for engine vs engine play. Is it that human books only have data gathered from human games and engine books only have data from engine vs engine games? I think not but could someone give me a little more insight as to why or how one book is considered better for human (like Powerbook 2008) and other is better for engine (like Rybka3.ctg). I am not so much interested in the comparison of these 2 specific books but more in theory of the difference between the 2 types

thank you in advance for your assistance

Well the only thing is that at many? levels of play (and at least the average) human players and computer engines have different strengths and weaknesses. My guess is that most engines are a lot stronger with tactics than us humans are, and they try to use lines to use this to there advantage. Everyone is different and chooses to play different lines for different reasons, but in general I think that is probably the case.

PerfectGent

Obviously these opening books are all used by computers or by humans preparing for humans by using computers for preparation; the "book" is not one made of pages of course. It is well known that there are different books whereby some are more suitable for human use/study and some are more suitable for engine vs engine matches; as such if I am preparing for a human vs human match I would use certain opening books (yes on my computer in preparation). If I am preparing for a match against an engine or engine vs engine then the opening book used for best possible outcome is not the same book... the opening books are different and specific to the purpose or goal. Regardless of the fact that they are checked with an engine, it is this difference that I am interested in understanding. The example I provided is a case in point. Powerbook 2008 is better used for human study and not the best for engine matches. Rybka.ctg or Perfect15.ctg are considered good engine books. Why??