An Introduction to GraphViz and dot (O'Reilly)
Michele Simionato
explores dot and GraphViz on O'Reilly.
"
First of all, let me make clear that dot is not just another paint program, nor a vector graphics program. dot is a scriptable, batch-oriented graphing tool; it is to vector drawing programs as LaTeX is to word processors. If you want to control every single pixel in your diagram, or if you are an artistic person who likes to draw free hand, then dot is not for you. dot is a tool for the lazy developer, the one who wants the job done with the minimum effort and without caring too much about the details."