I was surprised by how good this book was. Overall, first rate research and writing. There were, however, some places that could've used an editor's hand. A lot of typos and some parts that could've been streamlined. It felt a little like the editor took a break and just left things to the writer. It did get a little uneven once it got to the sealers, after Halley and Cook. But that's more than halfway into it, and everything up to that point was so well-written and so interesting. The sealers just weren't as compelling, so their part of the story can't help but drag a little. At that point, the editor could have started slashing material without losing much.