Here, you will find a small, but growing selection of popular-science books dealing with Einstein's theories - no formulae, no math.
Bartusiak, Marcia: Einstein's Unfinished Symphony. Listening to the Sounds of Space-time
Exhaustingly researched and engaging description of the hunt for gravitational waves - from the beginning in the 1960s to the construction of modern interferometric detectors. Apart from acquainting the reader with the basic physics, Bartusiak does a great job showing how science actually works - from funding politics to the human face of research.
Thorne, Kip: Black Holes and Time Warps - Einstein's Outrageous Legacy
W. W. Norton 1995
Thorough presentation of general relativity, from the basics via historical developments and astrophysical applications right down to wormhole time-machines (and a look at the media circus surrounding them). The focus is on the relativistic physics of compact objects, from White dwarfs to black holes. Thorne, himself a relativistic expert, clearly knows what he's writing about, and has himself played a role in the developments recounts. With lots of historical information, this book should be of interest not only to the general public, but also to physicists working in the field.
Greene, Brian: The Elegant Universe. Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory
The popular science book about string theory, one of the candidates for a theory of quantum gravity. In the opening chapter, the reader is taken onto an entertaining tour of both special and general relativity, itself a masterpiece of lucid explanation. Then Greene, himself a string theory expert, moves on to superstrings and M theory. A great book that has won justified acclaim; if anything, one might criticize the somewhat too optimistic picture of the status quo and future of string models that Greene paints, and the fact that the increasing complexity in the final chapters will likely overwhelm most readers.
Greene, Brian: The Fabric of the Cosmos. Space, Time, and the Texture of Reality
In how far is space absolute or relative? What does spatial separation mean in a quantum world? Why is there a past and a future? Following up on such fundamental questions, Greene takes his readers on a journey from Newtonian physics to quantum gravity where often times, for seemingly simple questions, modern physics has found fascinating and surprising answers. Written as intelligibly and engagingly as the Elegant Universe, but with a significantly broader scope.
Hawking, Stephen: A brief history of time
Stephen Hawking's "Brief history of time", now available in newly illustrated and expanded editions, is truly the classic of popular science writing about physics, and one of the best-selling popular science books of the planet. For millions of readers, this was where they first heard about curved space-time, black holes or cosmic inflation.
Hawking, Stephen: The universe in a nutshell
A colourful panorama of general relativity, quantum theory, time travel and brane worlds - with many playful professional graphics, with an emphasis on Hawking's personal areas of research, from black holes to his favourite candidate theory of quantum gravity, quantum cosmology with "imaginary time".