I read this a long time ago and I can't recommend it enough. It does a good job of introducing the concepts of stoicism and defending the philosophy from our modern assumptions of the word. A very good read.
The word 'stoicism' has kind of a bad rap, but I find it a very peaceful and comforting philosophy, and one I actively try to model my life against. Like most life philosophies it's not something that comes naturally or immediately; rather it's something to keep in the back of one's mind and actively strive towards over the course of years.
Those interested can also read Meditations, by Marcus Aurelius, and the Enchiridion, by Epictetus. Both are very short. Be careful with the translation you get of Meditations: if the first few paragraphs seem excruciatingly baroque, then you got a bad one--drop it and find a better translation.