Greetings, Friendlies!
Leigh Brasington recently self-published a new book on the Gradual Training; it is available on his website (dāna basis): http://gt.leighb.com/.
If you didn’t know, along with _Right Concentration_ (on the sutta jhānas), Leigh published a book on Dependent Origination, also available on his website: https://www.leighb.com/sodapi/index.html.
With friendliness!
Dharma PhD 