The manga guide to Calculus is a great book.  It helps me reason on a topic that is hard for me to grasp.  Someone must think SQL is a difficult topic too.<p>TACOP is extremely dense and put me to sleep every time I tried to read it.  I recently donated my copy of 0-4 to my work library, where nobody was interested in reading it.<p>The fact that we both have opposite views of your example books shows that this is a difficult process for librarians.