Warning, this blog entry devoted to shameless self promotion!
I've been working over the past 6 months or so to expand and improve my book on special relativity, Relativity Made Real, and I am pleased to announce that the second edition is now available on Amazon (print and Kindle). It was quite a labor of love, I must say, and I will be publishing two related papers, one of which should appear in the American Journal of Physics before too long.
The purpose of the book is to give a more physical, "nuts and bolts" treatment of relativity, to counterbalance the rather abstract spacetime-oriented viewpoint which one finds almost everywhere else. Just as one example, consider time dilation, the phenomenon by which moving clocks run slower than stationary clocks. What causes this to happen in specific, physically-constructed clocks? Every clock consists of some kind of matter which is constructed to execute some kind of repetitive, cyclical process; looking at specific sorts of clocks, it should be possible to understand how motion affects their internal processes without appealing to any abstract generalities about time or space. By doing this, one gains a more concrete understanding of the predictions of relativity, thereby (hopefully) making the theory seem more "real", which inspired the title of the book.
Of course, there is not a completely different set of mechanisms for each kind of clock and for each different phenomenon of relativity. There is an underlying, unifying theme, and this is the behavior of waves. Indeed, relativity grew out of the very first wave-based theory, the theory of electromagnetism, and this is no coincidence; furthermore, in our present quantum-mechanical understanding, every object in the universe is actually described by an underlying wave-based theory ("quantum field theory"). This deeply wavy foundation is what produces the strange phenomena of relativity.
And these phenomena are, in fact, not that strange when one thinks of them in terms of waves. You probably would not try to build a rigid object using waves - and relativity predicts that there are no rigid objects (things shrink when they move). Things made from waves inevitably "slosh" when they move, hence motion must affect them in all sorts of ways, and it is not that hard to understand the effects qualitatively by building on one's everyday experience with waves at the ocean, waves on a jumprope, or sound waves in air.
Anyway, that's a preview of the basic approach taken by the book; please check it out and let me know what you think. It is, I believe, completely unique in the popular relativity literature. Mermin's book (It's About Time) contains some similar material in its last chapter, and there is another book called Physical Relativity, by Harvey Brown, which definitely follows the same philosophy, but is not pitched at a popular level, and also places a much greater emphasis on philosophical disputes, historical viewpoints, and general relativity (Einstein's theory of gravity).