The thing about some authors is that you trust their heart. Their themes, their sympathies, maybe - but I really do think "heart" is the best word for what I mean here. Like - hobbits were and are and (probably) always will be my favorite part of Lord of the Rings, and there's no hobbits in the Silmarillion. So I could have gone in thinking I wouldn't find as much to love. But the thing is that it's written by the same guy who gave us the hobbits and their themes and their hearts. The same guy with the same views and priorities and eccentricities. Like, it doesn't matter that the story is about Elves, it's still got Tolkien's heart and themes, which was the thing that was shining through the hobbits in Lord of the Rings to begin with; the thing I love about them! Even Children of Hurin still has Tolkien's heart, and I can feel it through Turin's troubled heart. And now I love Turin and I love Tolkien Elves, too, for the ways they show that heart. What does it matter if the tale is of Elves or Men or Dwarves or hobbits? Tolkien can't help writing with the same heart, and I trust it.
Similarly (to me) with Dickens, or Dostoevsky. I knew the guy who gave us David Copperfield or Ebenezer Scrooge's story arc wouldn't let us down if I explored more of his work; it would still have the things that made me love those stories. The guy who gave us Prince Myshkin clearly values the things that Prince Myshkin stands for, and therefore I trust that man when I look at his other works. The Dickensian heart and Dostoevskyan heart have won my trust. Like, yeah, I couldn't quite appreciate "Demons" the same way, I don't love every CHAPTER of the Silmarillion or of Nicholas Nickleby, but I knew would find something there that resonated, because by themes and sympathies and resonances, I felt I knew the author's heart.