Abhidharma
The Abhidharma is the work done by the monks which came after the Buddha. They systematically organized, categorized and expounded upon the doctrines outlined in the Buddhas original discourses.
It is a scholarly work. It is dry to some. To others is is a fertile ground for understanding. Do you need to read this book and understand it to attain enlightenment? No. The authors say as much but knowledge is a good thing and it really helped me understand the doctrine of dependent origination.
You can read it here.













