As Jerome says - subscribe to Audible, then link your Audible account to your Alexa app (via the app - sorry, it's a while since I did this so I'm not sure I have all the steps but it wasn't difficult). Then when you want to hear your book, ask Alexa to open Audible and presto! your book starts up. You can go back a chapter (or forwards - check the Alexa manual on Amazon for the finer detail) and you can set a sleep timer so it will stop reading at some point, hopefully not long after you've nodded off.