Subtitle: The 300-Year Journey from an Idea to the Computer. Berlinski's prose occupies a hazy territory between fiction and not. The subject matter is fairly arcane and technical (I am guessing that 2/3 of the general populace doesn't even know what an algorithm is, much less care to read a book about its history). His idea of how to tell its story is to fill it with imaginary scenes such as Leibniz attempting to tell his patron, the Duke of Brunswick, about his new creation, except that the Duke interrupts him due to an incontinent bladder. You can imagine how that illuminates the invention of the algorithm.
Ok, so maybe it just illustrates how completely beyond the concerns of his time, and his contemporaries, Leibniz was. In fact, that is the most intriguing lesson in Berlinski's book: humans had been imagining something like a computer, and how it might work, for centuries before they ever had one. Charles Babbage is often given credit for inventing the first computer, but in some sense there had been software written and ready for it for about 300 years before the hardware appeared on the scene, and Babbage's scheme was but one of many instances of great thinkers wishing for a device that could execute an algorithm.
What is an algorithm? The key point would seem to be that it is a sequence of steps, each one of which is simple enough as to require no insight or creativity. It's a very peculiar way of thinking, if that is the word for it, and not one which comes very naturally to the human mind. Those who took more naturally to it (e.g. Leibniz or Turing) came along about once every hundred million people.
Which is Berlinski's biggest obstacle to writing a book about this, of course. How do you get people to buy a book about a topic which is intrinsically opaque and alien to almost every potential reader? It is apparent that Berlinski is a man without fear, in this regard; he has also published a book, not a textbook but a book intended for the general public, on the Calculus.
When explaining the idea of the Traveling Salesman problem, he presents us with an imaginary conversation, over dinner at a restaurant, with his editor and his agent. One wonders what his editor and agent feel at being cast as more or less fictional characters in his work. He returns several times to a dinner set by the Cardinal of Vienna, who inquires of physicists concerning time and space, meaning and logic. He concocts a new old story of a merchant who sells dreams, and an until-then satisfied customer comes to return a dream of truth which unfortunately included recursion.
In between, Berlinski juggles equations and graphs, theorems and pseudo-code as elegantly as any writer may, to bring us along with him as he attempts to trace the gestation of an idea across three centuries. Goedel and Church, Post and Peano, Frege and Hilbert, all cross the stage, as his tale hurtles towards its own nearly inexplicable ending.
The ending, is the tricky part. To what end has the algorithm come, thus far? It is hard to tell it in a satisfying way, for the very reason that it has succeeded so well that it has moved beyond what we could as easily calculate ourselves. Berlinski's ending is, perhaps, cruel, and not a little ominous, but it is affecting. The story of the algorithm is the story of our attempt to understand, and then reconstruct, the act of thinking itself, and to look long on such a topic is unsettling to the spirit and dreadful to the soul. Berlinski's periodic tangents into fiction and prose poetry, are like way stations of warmth and light on a trek across a beautiful but deadly landscape of ice and snow. The algorithm is currently transforming the planet, in a way which we have difficulty even perceiving in its entirety, much less comprehending. Come look at the history of how it came to be.