Acol Index, The Uncontested Auction, E. Crowhurst

A masterpiece of condensation covering every possible sequence of up to four bids. Use it for learning, settling arguments and correcting misunderstandings — or if you want to use your own interpretations then you have a standard to check against! Not for beginners but indispensible for regular duplicate players, even of systems other than Acol, who want to develop partnership understanding.