This was interesting but seemed like two separate stories that didn’t flow together very well. The world’s fair stuff and the architecture stuff was way more fascinating to me. I knew this book was something about a serial killer, but the Holmes stuff turned out to be less interesting to me - and the Holmes stuff never really felt integrated into the book. (And those sections also felt more speculative.) But I enjoyed the parts about the Chicago world fair - the planning, the building, and the execution. I learned a lot! There was a ton of stuff I didn’t know came from there - the Ferris Wheel, Pabst Blue Ribbon, and Frosted Flakes, to name a few. I kind of wish the book was only about that, with the Holmes stuff as a small aside.