This seems to be the standard biography on Einstein, and it's often listed in the bibliography of popular physics books. It's certainly thorough, but a lot of the content is quite technical and Pais doesn't shy away from quoting page after page of equations, and in all honesty I didn't follow much of what was said there. This leaves me a bit ambivalent about the book. It's sufficiently broad in scope that it ought to have some appeal to a general audience, but it's difficult to recommend as a whole because so much of the book is technical.
What Pais does successfully convey, though, is much of Einstein's character and open-mindedness, in particular with regard to work (Pais knew Einstein professionally as well as personally). He shows the broad range of Einstein's researches, of which relativity theory was a significant part but by no means the whole, and corrects the perception that Einstein had no time for quantum mechanics (he acknowledged its predictive capability but would not accept it as a philosophical basis for physical reality; ironically his Nobel prize was awarded for his work on the photoelectric effect, one of the earliest phenomena successfully explained by a quantum treatment).