Programming and Using Linux Sound - in depth

Jan Newmarch is writing an e-book on the topic:
"Programming and Using Linux Sound - in depth"
http://jan.newmarch.name/LinuxSound/index.html

This work is thorough! A good reference literature to have around. Looking forward to see Jan's updates.
It already covers OpenMAX IL and other hardware accelerated API's.
http://jan.newmarch.name/LinuxSound/Sampled/OpenMAX/