To those looking for a good book on SR, either for their own enjoyment
or to use in a college level class, may I recommend James H. Smith's
"Introduction to Special Relativity." Published in 1965, it hardly
represents the latest in pedagogy, but I find it thorough, careful,
clear, and generally superior to more recent books I've seen. It offers
not one, but three solutions to the twin paradox. It also postpones any
mention of the Lorentz transformations until half-way through, which
jibes with my "physics first, math second" prejudices.