Mark Gallagher is a great instructor, one of the best I have had so far at UCLA.
I had him for English 4w -- really funny and smart, very entertaining, too. He can be a bit intimidating because he teaches 4w like an upper level English course (lots of quoting and totally obscure literary references.) He has a tendency to talk a lot but you learn a lot from him, especially when he talks about Ralph Waldo Emerson or Henry David Thoreau (which is all the time.) It's cool because he has this crazy Boston accent which makes everything he says sound even more intelligent.
I don't think I can say enough good things about Mark. He's super passionate about literature and he is really serious about making you love it, too. Makes everyone in the class memorize a poem and recite it on the last day of class. He also is super helpful in his office hours. He pretty much is willing to go over every single one of your drafts and tell you what you are doing right and what you need to fix.
I have had a few English courses since then and I have yet to find a more knowledgeable and dedicated teacher.