Another oddly out of copyright book (pub. 1974) concerning Greek philosophy. Very effective introduction to Stoic philosophers and their ideas.
A certain positive: the book provides historical context on the thinkers. I actually learned much about Posidonius from this, despite years of familiarity with Stoic thoughts.
Nice short primer on the history of Stoicism, Stoic beliefs, including cosmology which is what I was most interested in, and all the notable Stoics and what each was known for. Very good book for reference
A concise, workmanlike summary of stoicism, focusing almost entirely on the earlier Stoics. If most of your knowledge of Stoicism revolves around Seneca, Epictetus, and Marcus Aurelius, this is a good source for getting a better sense of the origins and development of the philosophy of stoicism.
Excellent, concise, scholarly review of all major aspects of Stoic thought. Perhaps most useful in the modern era because Sandbach shows no undue reverence to the ancients and is comfortable criticizing their arguments where they are plainly contradictory or nonsensical.