This is definitely a book for the committed fan but if you are a committed fan, you'll definitely enjoy this book. The quality of writing is very good, well above the level of the great majority of sports journalism, and Wilson appears to be a very thorough researcher. The bibliography is impressive and Wilson deserves credit for grinding through and analyzing a large volume of material, some recondite in the extreme (club histories) and a great deal that must have been rather boring to read (memoirs by famous managers). The result is an interesting, comprehensive history of soccer tactics since the initial development of the game. There are a couple of recurrent themes. Wilson, as befits a Brit, is rather concerned with the state of British football, and the perpetual conservatism of British coaches and managers runs throughout the book. The corollary, the birth of innovation outside Britain outside Britain, even when fathered by expat British coaches, is another theme. Wilson also illustrates well how tactical changes often occurred somewhat in parallel in different countries, an interesting example of convergent evolution. Some changes occur because of rule changes, Herbert Chapman's development of the WM formation with stopper center half being an example. Others arise as logical tactical adaptations, for example, the development of the flat back four or the withdrawn center forward. Some tactical changes are set in train by others. With teams playing a flat back four, traditional wing play became obsolete. Some tactics, like the Swiss precursor to the sweeper, arose because of unique circumstances, in this case, a semi-professional league, and then spread.
There are some real surprises in Wilson's account. Who would have thought that the Soviet Union would host football innovations? In the 1950s, intelligent Soviet coaches were emphasizing aggressive forward play and diagonal runs. By the 70s, Ukrainian coaches were developing the aggressive full field pressing style characteristic of much of the modern game. Usual descriptions of Dutch total football emphasize its attacking propensity but Wilson intelligently points out that this was predicated on aggressive defending, pressing, and playing a high line and aggressive offside trap.
I think Wilson does make one significant omission about something that has influenced soccer significantly in the recent decades - the development of goalie play. The nearly universal existence of big, athletic keepers with decent ball skills is certainly one of the factors that permits the modern pressing game.