John Walker, a schoolteacher who has taught chess to children for many years, has effectively arranged his material in two parts. In the first, he explains the various tactical ideas and then tests them, but by theme or with hints; while the second part, which is the meat of the book, consists of 32 tests of six positions each, without any hints and of mixed theme.
As his title suggests, Walker is deliberately not aiming at the top end of the market, and his book is essentially a superior collection of the sorts of positions which I devoured voraciously as a child - mostly with heavy bloodshed within the first couple of moves.
However, tactics are the building blocks upon which all chess play is based and without some command of them a player would be lost, however great his or her strategic skill. So the study of them is an essential prequisite to progress and it is precisely to these "finger exercises" that I ascribe my tactical fluency (when I'm not blundering) today.
Any reader, particularly without such a collection already, could do far worse than to purchase this book. The following two examples are fairly typical.
Black to play
This is Walker's position No 129 (Heintze v Kruschwitz Grunbach 1951). With the b pawn about to queen, the case looks hopeless but Black forces an immediate draw with 1...g3+! 2.Qxg3 Qg1+! 3.Kxg1 stalemate!
Black to play
In position No 144 - Bagirov v Kholmov, Baku 1961 - Black forced an immediate win with 1...Rxe1+ 2.Rxe1 Re2!! when if 3.Qxf6 Rxe1+! or 3.Rxe2 Qxc3 or 3.Qa1 Qxf2+.