&gt; the same Jim Hefferon<p>Yes.  <i>Linear Algebra</i> with answers to exercises and lab manual, and an <i>Introduction to Proofs</i> that a person can find referenced on that page.<p>&gt; Would you consider spending a lot of time and effort on a book (.pdf) in your research area - for no material reward? To be read by a very small audience? Orders of magnitude smaller than undergraduates looking for a good linear algebra text?<p>I am saying that people can put the books discussed in the article online.  The fact that they are niche, or not, does not seem especially relevant, to me.  I spent thousands of hours on the text; it is a professional activity that I think has helped people.  The last I checked LA gets about 30K downloads per week, but even a book for specialists that gets 10 downloads per week could live online.<p>In academia, the great majority of authors do not get money from a book that in any way comes close to the effort involved, in my experience.  It is a professional activity for most.  The publisher in this article may make a good living but the authors do not, again in my experience.<p>I have nothing against traditional publishing but I think online is an alternative.<p>I do think, though, that there needs to be a way to curate and review the works.  They need to be gathered online in some kind of CTAN-like thing because, among other things, busses happen.  They need to be reviewed because, among other things, tenure and promotion happens (or doesn&#x27;t).<p>But, if those two things are done, I think that an alternative or supplement to paper versions makes sense.