Oh, definitely. There are dozens, maybe a few hundred agencies around the world. Photo agencies are basically a requirement at a certain level and both art photographers and commercial photographers have them. They're the ones who will do all the work of getting you into galleries, booking decent shoots, working with models and their agents, etc.
Big firms won't even look at you unless you've got a monster portfolio and world-class , but you can find smaller agencies that will work with people of all levels of success and fame. There are also publicists who will do a great job of getting your name out there. Your name is your brand, and your success translates into their success. It's an ugly truth, but a lot of a photographer's impact lies in all the promotional work that people do for them before anyone even looks at a photo. What's the first thing you look at on a new instagram account? The number of followers? Or the photos? Be honest.
So, yeah, if you want a photobook, it's likely that your agent or manager would start that process. But you'll need a gallery showing first, or an instagram following so big that you can't be ignored. You can also self-publish and self-distribute, which is what a lot of photographers end up doing in the beginning.