I am currently reading this book and also find it a good modern interpretation. It has a concise background on the stoics and combines and interprets the teachings of many of them in to an easy to understand principles. I bought this in combination with Seneca's "letters of a Stoic" and "Meditations", by Marcus Aurelius thinking it would a good introduction before reading these.

I have noticed many of Stoic practices reproduced or supported by popular religious practices which makes sense if they aid in practitioners feeling the tranquillity/happiness that the stoics sought, even if done through fables and commandments.