I suppose TBoB is the only one that says "HEY GUYS THIS IS ABOUT THE HISTORY OF BASKETBALL" but for my money it's actually The Rivalry that does the best job of covering the changes in the NBA.
Sort of the same way The Metamorphosis says more about the human condition than War & Peace does, even though one is more explicitly historical in description and setting.
And yes, the free darko book is phenomenal (both free darko books, are). It is much more like a history textbook than you might think from the ad copy/reviews, though.
If nothing else, Simmons gets people (and especially C's fans) excited about talking about writing about sports, which is awesome.