I listen to a lot of audiobooks, read a lot of library books and e-books, still somehow never have enough room on my bookshelves.
The planning we were threatening to carry out was best described by a skeptical Pentagon colleague: "We send in a series of increasingly larger probes. If they're all stopped, we fire a [nuclear] warning shot. If that doesn't work, we blow up the world."
Which seems to have been the core of US nuclear strategy from about 1946 to the present day. It's not like I didn't know about MAD/SAD, but seeing it laid out clearly and logically is something else again.
The strongest parts of the book describe Ellsberg's own "confessions" and his involvement in assessing and forming US nuclear policy in the '50s and '60s, as well as descriptions of the Cuban Missile Crisis (even scarier than you thought!) and other key events in that time. That takes up the first two hundred or so pages. The descriptions are often darkly funny in the line of a Terry Gilliam movie, and are especially interesting for Ellsberg's descriptions of the cold warrior mindset and how he himself was almost completely sucked into it (so much so that he didn't even register his own participation in the brinkmanship of the day until decades later).
The latter hundred pages or so of text describes the evolution in US policy starting with city bombing in WWII that led to "blowing up the world" being on the strategy table at all, the way the US has used threat of nuclear attack in its foreign policy from Truman through to the present day, and some tentative suggestions as to how to undo this mess. This section is interesting, but not as strong, and I wish the "dismantling" part had been about fifty pages longer and more specific. Ellsberg seems to more or less have dropped that part in the lap of the next generation. Which is his right, but the books could have used a stronger conclusion.
All and all, it's well worth reading for the history, especially if you're a fan of sites like Nuclear Secrets. As a Canadian, I can mostly hope and prey that good sense prevails in Russia and the US.