– Scott McCloud
This is book one of three in a series, but after reading it I skipped the third and only kept the second.
One of the early texts of literary criticism specializing purely in the medium of the graphic novel. Supposedly it is the seminal work in the field, or at least the breakout text that made the field more accessible.
His theorical support towards it is astute and covers a very wide area, including an explanation on the nature and semiolitcs of cartoonistry. I believed for quite a while that the first member of my family who ever wrote a master's thesis used McCloud prominently as a supporting source in her explorations of drama in education, but I was mistaken; it was actually Art Spiegelman.