What's your book about, Lee?

I've found that scope management is important. With the first edition of my Software Requirements book (1999), I had lots of ideas for topics to cover, but I also had (and always do have) a target length in mind. I had to prioritize the topics, and sometimes the depth of treatment, to stay focused and keep the length manageable.

All the leftover topics made it into the second edition in 2003, although I wasn't planning to do a 2E initially. I just had to draw the line somewhere.

It sounds like you might need to step back and think carefully about exactly what your book is--and is not--about so that you can decide what's in and what's out, thereby increasing your chances of completing it. Good luck!