Historical Sci-Fi Full of Twists

I can't imagine the detailed notes the author must have had to work and rework to make this novel happen. It's a tricky and twisty body-swapping mystery that never goes where you think it's going to. That being said - Did I enjoy it? I'm not sure. I loved the concept. It's historica l(at least seemingly so) but also sci fi (a rarity!) and the description definitely pulled me in. However, after the hooking description it became too ponderous and dragged on too long. It's great to not know what's happening until the last 10% of the book, but when the book is as long as this one not knowing what's happening can start to lose your interest. I wish the editor had helped edit down the length, because it definitely had potential.