After a sunday of woodworking in his workshop, A Reader likes nothing more than a stiff drink and a good book. So here are a few choice quotes from Leonard Susskind’s book *The Black Hole War*.

The real tools for groking the quantum universe are abstract mathematics: infinite dimensional Hilbert spaces, projection operators, unitary matrices, and a lot of other advanced principles that take a few years to learn. (p. 75)

Grokking is Heinlein’s term for developing such an understanding of a field that its nature becomes almost intuitive. I’m not sure that it really applies here, but perhaps for super-smart physicists it does. It also has two ‘k’s. The book will try to explain black holes without the math, Susskind tells his readers.

A black hole horizon is the most concentrated form of information that the laws of nature allow. (p. 116)

This is a very deep insight, and it’s the solution to the problem that Susskind found with Hawking radiation: when matter comes into a black hole, all information in that matter is preserved in the black hole; if the black hole dissipates its mass (or energy) as Hawking radiation, which carries no information, then information is destroyed, something that violates quantum mechanics.

The rest of the book will describe the evolution of the problem and its current solution of the universe as a hologram (a structure where all the information is contained on the surface area rather than the volume).