The Elegant Universe

Physics enters the twenty first century with an embarrassment at its centre: its two great theories, general relativity for the large and quantum mechanics for the small, are each spectacularly confirmed and mutually incompatible. Greene's book is the case that string theory resolves the feud, and it became the standard public account of the most ambitious idea in modern physics.

The exposition is the achievement. The first half is the best short course in twentieth century physics anyone had written, special and general relativity taught through moving trains and accelerating elevators, quantum weirdness through interference and uncertainty, each with images that stick. Then the strings: the proposal that the fundamental constituents are not points but tiny vibrating filaments, each particle a different note, gravity emerging naturally from the music, and the mathematics demanding, rather than merely permitting, extra spatial dimensions, six or seven of them, curled at every point of space into shapes called Calabi-Yau manifolds, which Greene, a specialist in exactly that geometry, describes from inside. The tour ends at the 1995 second revolution, dualities, M theory, eleven dimensions, black holes counted string by string.

Greene is honest about the standing debt, that the theory had yet to make a tested prediction, and optimistic about its payment, which is where the argument has stayed.

Around four hundred and fifty pages, demanding no mathematics and full attention.

Best for readers who want the string theory era explained by a believer with a gift, and the clearest popular relativity and quantum primer in the business as the price of admission.