This truly was an excellent book. It was exciting, thrilling, engaging, entertaining, intellectual, informative, and daring. It is a testament to its time, its author, and its genre.
Its ending is most exquisite. The tying together of various wandering knots in the tale to form its resolute end kept me on the edge of my seat for the last four chapters, easily. The encounter with the cephalopods, the battle with the mysterious vessel, and the drive into the maelstrom form an exciting conclusion to this book.
The middle, however, is where the book suffers. It is, at times, too slow. While its science fiction is entertaining and intellectually invigorating, it strays too far from the story to engage therein. On the other hand, the discussions of species of fish, the questions of history and natural history, and the variegated adventures of the professor and his companions are all necessary and appropriate to that story. Even so, they tend to drag on from time to time (one of many reasons I was not able to finish this book more quickly).
All that said, the book is definitely worth the read, especially if you love science fiction. It’s one of the classics for a reason.