Endless books, with endless details, only a few of any importance. It doesn't take a book of this size, or Piketty's previous one, to explain the existing financial structure: the Big Four investment firms, or various combinations of these Big Four firms, are the majority shareholders of the major corporations of North America and Europe and am uncertain of elsewhere - - since I have finite time and resources???
With subtle cross-shareholding their asset value and control is magnified to an unfathomable level.
Example: In cross-shareholding between two corporations, their asset value and control is magnified four times - - between four corporations, it is magnified sixteen times - - between eight corporations, it is magnified sixty-four times, i.e., exponential increase.
Hence, cross-shareholding by four or combinations of those four [as in two or three] among many thousands of corporations yields almost unimaginable financial power and control!
Now that did not require 500 to 1,000 pages, did it?