Practical Clojure (http://www.apress.com/9781430272311)
ClojureScript: Up and Running (http://shop.oreilly.com/product/0636920025139.do)
Clojure Cookbook (http://shop.oreilly.com/product/0636920029786.do)
Practical Clojure and Clojure Cookbook were/will be available in B&M stores though those are a relatively small fraction of sales. ClojureScript U&R is print-on-demand/ebook only.
In each case I wrote the books because I felt I had something to say, and was qualified enough to say it. Getting published was mostly a matter of being in the right place at the right time, when the publishers were interested in these books, and being introduced to a couple editors via coworkers and open-source acquaintances.
Niche tech books like this are not a good deal from a purely financial perspective. I make some money, but somewhat less than I would contracting for the time I put in to them.
They were very valuable or forcing me to gain mastery of a topic, and they are quite possibly the best thing I've done with respect to my career.
Fresh book recommendations delivered straight to your inbox every Thursday.