Cost benefit of publishing academic books,

Nature has just published an editorial (http://www.nature.com/nature/journal/v463/n7281/full/463588a.html) promoting the idea of writing text books (http://dx.doi.org/10.1038/463588a).
Having worked for a number of years as a commissioning editor for a
major academic publisher, responsible for more that 20% of academic
book output, I have to say that the cost-benifit analysis for
publishing books ends up saying that it just does not justify the
effort for academics to write monographs. You probably won't see more
than a few hundred sales, citations to the work will be slow in
coming. Early career academics in particular are wasting valuable time
that should be spent on getting publications out. That said there are
three situations in which it might be OK to be involved in producing a
book:

1. You are at an advanced stage in your career and you want to codify
your vision of a particular subject. In such a case the work is a
labour of love, you have your laurels and now you want to produce an
artefact that synthesises your view on a topic. This is a highly
valuable exercise, look at the works of Chandrasekhar for an extreme
example of this. Of course, such an individual is going to go ahead
and do this anyway.

2. You have been instructing a class and have put together a detailed
set of instructional notes, especially for advanced classes in
graduate school. For a little more effort you can convert a large
batch of work that you have already done into another artefact that
can increase your academic reputation, go for it!

3. You are involved in a large consortium or working group. The act of
putting together a chapter for a book can cement working
relationships. What tends to be more important here though is the
collaborative process, more-so than the final artefact. The question
to be asked should be whether working with the given group of
academics is worth the time, rather than whether the final book will
be worth the time involved.