I'd be happy to suggest what I've found useful! However, the philosophy is expansive and old, so there are too many possible recommendations - it depends on what you're trying to accomplish. A broad survey of its principles? A straight-forward introduction? Modern attempts at reform?
May I ask for the straightforward introduction recommendations in place of GP? I found your comment very interesting -- my understanding of either is still very rough, but as I was reading through Feeling Good[1], I had the feeling that on a practical level, both were attempts at finding out "how to take it as it comes" (excuse the hasty reduction). I did not know of the direct link between them, thanks for that bit of knowledge.
I liked “A guide to the good life” by William Irving, which covers the history, techniques, and advice from the big names of Stoicism.
I wouldn’t call myself a Stoic, but I have a lot of anxiety from my job and life and found this book helpful in changing the way I think and feel about situations in life.
