Meditations by Marcus Aurelius
I love this stuff. This is one of the quintessential Stoicism books. I learned about Stoicism by tracing SMART Recovery back to Albert Ellis, who credits REBT to Stoicism. There is a lot of information about Stoicism on the internet if you're interested in learning. The Stoic Emperor Marcus Aurelius has some excellent Stoic advice for himself in this book. Little did he know someone would make it public.
This book is a private insight into the Roman Emperor Marcus Aurelius. Legend has it that he would write in it and read from it daily. It is said that he wanted no one to ever read it. It was his secret sauce. Yet here we are. Published a million times. This is the secret information that kept him who he was. Momento Mori. Why he is said to be one of the greatest Emperors ever.