See the link box in the upper right corner of this article for links to the two reviews (and to a definition of repertoire if you're not sure what it means).

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The family of opening books is a large one. Where do repertoire books fit in? Looking at the universe of chess books, we find four different types of works on the opening.

• Introductory books like Reuben Fine's classic Ideas Behind the Chess Openings • These explain opening principles in broad terms, like the difference between 1.e4 and 1.d4, or between 1.e4 e5 and 1.e4 e6 • They are unbiased in that they treat White and Black equally. Their analysis of specific variations illustrates general principles.
  
  
• Comprehensive books like the Encyclopedia of Chess Openings (ECO) & Modern Chess Openings (MCO) • These are surveys of the main lines in all openings. They are unbiased toward White and Black. As compilations of thousands of specific variations, their limiting factor is the size of the book.
  
  
• Repertoire books like the two books reviewed for this article • These are in-depth surveys of families of specific openings. They are usually aimed at White or Black, but not both. Their goal is to give you enough knowledge to reach a good middlegame given sound opening play by your opponent.
  
  
• Books on specific openings like the Scheveningen Variation in the Sicilian Defense or the Panno Variation in the King's Indian Defense • These books are in-depth surveys of the most important lines in one opening variation. They usually cover all reasonable responses for White and Black. They can be used to prepare either side, even when they have a bias for one color or the other.
  
  

Getting back to repertoire books, it's important to know the author's reasons gives for recommending the moves and variations in the book. Two extremes are

• lines that are considered the most theoretically important (which often means the most popular) in an opening; or
  
  
• lines that avoid the most theoretically important variations.
  
  

The right type of book for you depends on your own style and whether you want to spend time studying and memorizing the games played by the top players. For more about developing a repertoire see our three part article 'Build an Opening Repertoire' (link box again).

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Since we're reviewing two repertoire books at the same time, it should be interesting to compare their suggestions on overlapping variations. The Collins book for playing White is based on 1.e4. The Lane book for playing Black recommends 1.e4 d5, known as the Center Counter Game or Scandinavian Defense. Both books consider 2.exd5 to be the best move for White, after which Lane recommends 2...Qxd5 over 2...Nf6. Both authors agree that 3.Nc3 is best.

Now Collins concentrates on 3...Qa5, the most popular variation among top players, and comments that 'alternative Queen moves are worse'. Lane rejects this advice, 'It had generally been acknowledged that the best way to try and achieve equal chances in [the Scandinavian] was by 3...Qa5. This view is now debatable and the trend is towards the neglected 3...Qd6 which can plunge White into uncharted territory.'

After 3...Qa5, Collins gives preference to 3...Qd8 as 'the most respectable of the alternatives', and says, '3...Qd6?! is a little more dodgy'. [See Glossary : Annotation if you're not sure what '?!' means.] He continues, 'A good, aggressive treatment is 4.d4 c6 5.Bg5!? and gives a long line starting 5...Nf6 6.Qd2 Bf5, where he concludes that White has, 'an excellent game, as in Svidler - Cicak, European Club Cup 2003'. What does Lane say about 4...c6? Absolutely nothing! He gives eleven games with 4...Nf6, three with 4...g6, and none with 4...c6. On Black's fourth move we have a difference of opinion between two strong International Masters (IMs).

Who is right? We admit that we don't know. Even after you've read through every opening book you can find -- repertoire or otherwise -- you still have to work some things out for yourself. There is no magic wand, no philosophers' stone, to lead you to the truth. Good repertoire books, like the two we've discussed here, are guides, not maps. Chess is a big mystery, a fact confirmed time and again.