This book is the journals and thinking of Roman Emperor Marcus Aurelius. His collected thoughts on how to live a good life, how to deal with ones Mortality. How to be a good man. It's old, its simple, but it has some very useful insights that apply even today. It is essentially an early self help book, leaning heavily on Stoicism as it philosophical grounding. Theres a lot of emphasis on personal responsibility, making meaning for oneself in the face of death and Oblivion, and contemplating what it is to be a good man, or to live a good life.
'If you are distressed by anything external, the pain is not due to the thing itself, but to your estimate of it; and this you have the power to revoke at any moment.'
'The soul becomes dyed with the colour of its thoughts.'