It's not hard to pinpoint Daniel as the protagonist of the novel – it's named after him, for crying out loud. Daniel is the guy that we want to root for. We learn all about him, watching him grow from a little boy (well, at least through flashbacks) to a young man uncovering his identity. He's a young guy trying to figure out who he is, and we're with him every step of the way.
Still, a lot of critics have wondered whether Daniel really is the protagonist of the novel or if the title is just a distraction – some people suggest that the title should be Gwendolen Harleth instead, because of all of the time we readers spend with our gal Gwen (for more on that, see our section on "Sorta-Protagonist: Gwendolen"). The debate over the identity of the "real" protagonist of this novel is just another example of how complicated and controversial discussing literature can be – there's not always one simple way to look at things.
Hear us out here. Two protagonists in one book? Well, yes and no. For decades, critics have struggled over what is the main storyline of this novel, and a number of people have argued that Daniel Deronda is really two books in one: there's the Daniel/Jewish plot and there's the Gwendolen/Romance plot. Some famous critics like F.R. Leavis have argued that the Gwendolen story is the central plot itself. Others cry foul on this assessment, saying that people want the story to be about Gwendolen because they are anti-Semitic and don't want the story to be about glorifying Jewish identity.
Let's put these controversies behind us for a minute and just focus on Gwendolen, though. The first 100 pages or so of the novel are almost all about her; in fact, even though the opening paragraphs put us inside Daniel's mind, we spend an overwhelming amount of time with Gwendolen. She's not just any stock character, she's not the romantic interest, and she's not the antagonist. In a lot of ways, you could argue that Gwendolen is one of two protagonists of the novel.