definitely seconding understanding comics!! theres a free pdf online if you look - and trust me, you will not get bored. its a really great read, brilliant flow. when i first read it it blew my mind, and i come back to it at least once a year for inspiration.
similar comic theory books that i recommend:
- will eisner: graphic storytelling and visual narrative
- will eisner: comics and sequential art (these are both prose books)
- matt madden: 99 ways to tell a story (experiments in form)
- chrissy williams: over the line (prose book with comics included, an introduction to poetry comics)
- also, scott mcclouds other two books in the -comics series: reinventing comics and understanding comics! reinventing is a bit out of date, but has a lot of great comics history and business talk, and making comics is a brilliant introduction to... well... making comics
also, some comics thatll inspire you:
- art spiegelman: maus. two-part graphic novel about the holocaust (beware, its heavy stuff), historic in winning literature awards, giving comics weight as a literary art form
- alison bechdel: fun home. memoir about a lesbian's strained relationship with her closeted dad - also heavy, and pretty sad
- richard mcguire: here. this is one of my favourites - from a formal perspective it will blow your mind. it takes a single space and follows it - non-linearly and in really cool ways - across all of time
- nick drnaso's sabrina has been making waves recently as well - it was longlisted for the booker prize (a first for comics). its next on my reading list
- emily carroll: through the woods. gorgeous gothic horror short stories
- emil ferris: my favourite thing is monsters. this HULKING GREAT TOME is written as the comic journal of an 11 year old girl in late-60s chicago as she obsesses over monsters and processes all the injustice she sees around her. it is really heavy and dense, requiring multiple reads, but its also super rewarding
i hope you enjoy some of these, and i wish you luck in your explorations