There are a number of Books, but most of them are pretty hard stuff. Can I ask what your background is and what you need it for?
-Do you know the theoretical Background of NMR (Bloch Equations, Density Operator Formalism, basic pulse sequences)?
-Do you only want to know cw-EPR or are you also interested in pulsed and in double resonance methods (ENDOR,ELDOR-detected NMR, DEER/PELDOR)?
-What kind of systems would you like to investigate (Organic radicals, transition metal complexes, Metalloenzymes...)
I might have a lecture script for you which is better suited for an introduction than most books.
spectral assignation
Note that this is not as straight-forward as in NMR, especially in the solid state. It often needs simulations... (
http://www.easyspin.org/)