I'm just wondering if the textbook is still actively being written. I've noticed that a portion of the semi-conductors section is "PENDING" and I was wondering if that's going to change anytime soon.
Yes, sign up here if you have questions, it is a friendly community, and the e-book writers are very active members here.
AFAIK, there will be more added on types of capacitors, expansion to the semiconductor/transistor area, and some on RF. I don't know the exact roadmap for sure, though these topics are mentioned now and again with regard to the e-book.
Judging from myself, writing the e-book resembles the process of cleaning your attic. You think about doing it everyday, but don't bring yourself to do it until spring comes.