**Book Review: Relativity - The Special and the General Theory, by Albert Einstein (with introduction by Nigel Calder)**

Special relativity was one of the first topics I studied as an undergraduate, and one of the few that didn't require mathematics beyond A-level. General relativity, on the other hand, was off the syllabus, even for final year students specialising in theoretical physics, and I've always been frustrated by that. I may have read this book as a teenager, I'm not sure; I certainly recall reading Bertrand Russell's

*ABC of Relativity*, which was described somewhere as

*lucid*but seemed to me to be the antithesis of the word. Anyway, Einstein's own account of both theories is very readable, although the non-specialist should be warned it does not dispense altogether with equations (though skipping these would not severely dent the book). Mostly the text is an argument of logic, based on some self-evident axioms, and one less apparent, at least to physicists in the late nineteenth and early twentieth centuries (the invariance of the speed of light from the velocity, relative to its source, of an observer). About half of the book is assigned to special relativity, and as such didn't offer me any insight, but was well constructed; and most of the remainder is assigned to general relativity. Although Einstein avoids going into detail on the maths here, it does at least give me a few hints of what tensors are about and how they could produce his theory, so I think it can be counted a success.