Reddit reviews Soccer in a Football World: The Story of America's Forgotten Game (Sporting)

Assuming that you're American.

Here's what you want to start with:

• Inverting the Pyramid, by Jonathan Wilson. This is an essential volume that goes over the evolution of football tactics in a way that anybody can understand. It also describes the best footballers of different eras and explains why they were so exceptional based on how they played the game rather than on their statistics. That is: a player like Puskas wasn't great because he scored loads of goals as a number-10. Rather, Puskas redefined what a number-10 is, and what that role does. An absolute must-read.
  
  
• Soccernomics by Simon Kuper. This is basically behavioral economics (think Freakonomics) applied to football. Looks at questions like: Is home-field advantage a thing, and how does it work? Why are penalty kicks a perfect example of real-world game-theory? And do England really underperform? Fascinating stuff, even though I don't buy it all completely.
  
  
• Distant Corners, and Soccer in a Football World, by David Wangerin. These are companion volumes that form the definitive history of the sport in the US, which is a lot older and a lot crazier than you think.
  
  
• Soccer in Sun and Shadow, by Eduardo Galeano. This is the sort of book you'll read cover to cover in one or two sittings, then leave in your bathroom, because you can flip to any page and read simply magical ruminations on the game. Even in the English translation (Galeano was a renowned Uruguayan journalist and novelist who wrote in Spanish), the short reflections out of which this book is built will give you shivers.
  
  
• Scorecasting, by L. Jon Wertheim and Tobias Moskowitz. This isn't really about association football, but rather more behavioral economics applied to sports in general. It will change your mind about a lot of the accepted "wisdom" that exists in all sports. Should you go for it on fourth down? (In many cases, yes.) Should you save your "closer" for the ninth inning? (Probably not.) If a player has sunk three three-pointers in a row, he's hot and I should get him the ball for another three-pointer, right? (Not according to the data.^* ) A great read.
  
  
  
  

This book helped me understand our history better. If you get a chance it goes pretty in depth about the leagues and there fall.

I'd recommend reading a couple books if you really want the answers you're looking for:

Soccer in a Football World

Distant Corners: American Soccer's History of Missed Opportunities and Lost Causes