[mark_l_watson]

You make good points. I used major publishers like McGraw-Hill, J. Wiley, Springer Verlag, etc. for the first ten books I wrote. You really give up a lot of control over subject matter. I now use Leanpub, write whatever I enjoy writing about. I pitch the advantages [1] of writing to people I know, and usually suggest writing one or two books with a publisher and after that self publish.

[1] largest advantage is getting to meet and get to know really interesting people. I enjoy writing but being an author also opens up a lot of opportunities.