Paul S.
Yelp
It really doesn't get much better than a specialist bookstore, especially one largely dedicated to art and architecture. In fact, the only comparable bookstore I'm aware of is in Culver City near the studios, so that makes Hennessey & Ingalls the masters of the LA Arts District.
First, this is a huge store, chock-full of new and used books, as well as out of print ones, and a large rare books section. Once I worked in the used book market, and I could tell immediately upon entering, and while browsing, that this shop is truly the real deal. Essentially, it's a giant, well-curated trove of art related books big and small, but if you're in the know, most art books are quite large and heavy.
In order to sell books here you're going to need a helluva collection and in tip-top condition (i.e. No moldly basement books, no dust bunnies, missing dust jackets, and especially NO Fucking self-help, mystery, best sellers, or romance novels). None, what you need are art, photography, and related subjects in excellent condition, preferably out of print, and uncommon is a plus. Then, you must schedule an appointment with the owner, so call ahead to see how that works.
I found the prices to be fair considering how expensive such books tend to be, I'm sure they have periodic purges and some used books are remarkably inexpensive and often given the "Brodart treatment', which is a mylar cover to protect the old dust jacket, that also enhances the appearance of the older books.
In short, I suggest checking them out.