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.








