This is the second edition of their introduction to special relativity. At around 300 pages long, it feels a fairly long-winded introduction to the subject. In the middle there is a fair amount of padding and repetition. Overall, however, it supplies an extremely readable introduction to special relativity.
There are a number of reasons for this. The initial approach is intuitive rather than formalised mathematically, although the maths is there (but the text is never really maths-centric). The choice of presentation makes the concepts very clear (with a strong focus on the invariance of interval and (rest) mass). "Paradoxes" are clearly explained, the style is chatty, and every chapter has an excellent set of exercises. It's an easy text to learn from.
The downside, as I mentioned earlier, is a certain lack of pace. If you're willing to skip through to run at a pace that suits you, it's a great introduction to what is, in the end, some remarkably simple and elegant ideas.