Loch Ness isn't the only body of water with monsters. In this book, Michaels looks at water monster stories from Central and South America. He does so with a good dose of healthy disbelief. So while he wants the stories to be true, she does not disregard rational reasons.
He does have discussions about the various legends, and at one points, goes off into wondering about if dinosaurs are still around.
Still it is a nice little collection of, at the very least, folklore with good and helpful footnotes.