I recently discovered a very interesting book about electronic ballast designs, it covered fluorescent ballasts, HID ballasts, neon drivers and reference designs as well as auxiliary circuits such as APFC. It is very comprehensive but unfortunately it's in Chinese, nevertheless I think it is a great resource to share here.

http://www.mcuzone.com/ebook/ZLQ_YYZZ.PDF

Thanks a lot! Interesting read.

Learned about a couple of exotic bipolar transistor topologies I never heard before - H2BIP and GAT transistors.

Very comprehensive on electronic fluorescent ballast design, yes, but a bit weak/dated on HID lamp ballasts schematics.

It was written back in 1999 and HID technology definitely came a long way after that. This particular book is also mainly aimed towards fluorescent ballasts only covering other types of power supplies briefly.