In the Introduction, Asa writes: "In 1969, I began to play the Czech Benoni. To tell you the truth, I do not recall how I first discovered it. Being a 1.e4 player in those days, no one would have had a chance to play it against me, though once I took it up I basically stopped losing!"
The opening moves to the Czech Benoni are 1.d4 Nf6 2.c4 c5 3.d5 e5 4.Nc3 d6 5.e4 e7.
After which, "White now has no fewer than 15 reasonable moves!"
In the 13 chapters that follow, moves such as 6.f4, 6.f3, 6.Nf3, 6.g3, 6.Nge2, and 6.h3 are analyzed with many illustrative games.
As I know from first hand experience, Asa is a fine positional player who understands that chess is a battle for squares.
For instance, Asa describes the above position, as follows. "With pawns on c5 and e5, d4 is an ideal place to put a piece, as if it is captured it will be replaced with a protected passed pawn, which may serve as a valuable insurance policy in any ending."
Besides the co-authors, practioners of the Czech Benoni include Joseph Blackburne, Anatoly Lein, Yasser Seirawan, Tigran Petrosian, Tony Miles, Miguel Quinteros, William Hartston, Garry Kasparov, and Magnus Carlsen.
Asa is also an excellent tactician, winning this game with his "favorite five-piece attack."