The Japanese have a word for it: tsundoku, a blend of the words for reading and letting things pile up. The term refers to the books we buy but somehow never get to, what the economist and deep thinker Nicholas Taleb, writing with respect to Umberto Eco’s famed 30,000-volume library, calls an “antilibrary.”

If we had to guess which book figures most prominently in the antilibraries of the world, Stephen Hawking’s A Brief History of Time, which appeared in 1988, might just be it. It was an unlikely bestseller, full of thorny concepts in physics and mathematics along with tentative stabs at presenting the unified theory of everything that his fictional acolyte, Sheldon Cooper of The Big Bang Theory, was still beavering away on 30 years later.

Unusually, Hawking also floated ideas about religion in his book, which went on to sell more than 10 million copies worldwide. He wondered whether there was such a thing as free will given that the presumed unified theory would also determine our actions‚ meaning, as he writes, that “the theory itself would determine the outcome of our search for it”—and perhaps decide that it would prefer to hide from our prying eyes. Certainly, what Hawking called “the God particle” eluded him even as he made important discoveries about the form and behavior of black holes and other features of space that were conjectural long before they were ever proven.

One of the things that makes my head hurt is the thought that one day, billions of years from now, the nuclear reactions that make the stars burn will come to an end, and when that happens, the universe will simply go dark. Stephen Hawking’s head hurt when he tried to puzzle out the thought that, as he writes, “the universe is not infinite in space, but neither does space have any boundary.” It’s a koan, that finite but borderless structure in which, improbably, we live, and Hawking returns to it at several points in his book.

Arthur Eddington, the great mathematician, once remarked that he did not consider any of his proofs complete until he had written them out in plain English. He was inspired by an Indian autodidact named Srinivasa Ramanujan. Another mathematician once visited him in hospital and remarked that he had taken taxi 1729 to get there. Ramanujan replied, “It is a very interesting number. It is the smallest number expressible as the sum of two cubes in two different ways.” (The cubes in question are 13 + 123 and 93 + 103.)

Stephen Hawking wrote in the same plainspoken spirit, difficult though his ideas were. While Ramanujan died at only 32, Hawking lived an unexpectedly long life considering that a motor neuron disease confined him to a wheelchair for 55 years. He died two years ago, at the age of 76, having received just about every award science had to offer—all, that is, except the Nobel, for the “God particle” about which he theorized was discovered, in the form of a boson, by another scientist. Hawking is gone, but A Brief History of Time remains in print three decades after its first appearance, waiting to be read.

Gregory McNamee is a contributing editor.