But I'm hesitant to release the LaTeX source files in their current (rather grungy) form. Too much of a control freak, I guess. Maybe for the next edition.
Also, the figures are all in a closed file format (OmniGraffle). In principle, I could convert everything to an open-source format like svg, but (0) converting everything would be hell, (1) LaTeX doesn't understand svg files directly, (2) in principle, I can connect latex to inkscape to convert svg to pdf, but the translation is always imprfect, (3) using Inkscape makes me want to tear my hair out, and (4) I'm a control freak.
And don't even talk to me about tikz.
Though I think the benefit would be less about just releasing the source, though the Open Data Structures book makes a compelling case for that, but fostering collaboration on the content. The books you mention have overlapping content and my heart really wants to join them in some glorious whole :)
Maybe that's crazy, the books clearly have different styles, but I feel like writing more advanced texts as extensions to an evolving intro book would be better for self-learners than just having the books stand alone.
FYI, the link to your course materials on http://opendatastructures.org/ seems to be broken now.
Maybe having a separate set of problems for the online version, with solutions, would be appropriate?
I have been wondering this for all freely available textbooks: have you ever thought about turning your book into an open source project? I see you already manage issues on GitHub, but how about managing the actual content there as well?
Producing a printed book might need tighter editing than shipping software, but I feel like there are a lot of books with partially overlapping content, and I feel like self-learners would be better served by larger books that are not meant to be read end-to-end, but that are "integrated" into a larger whole.