First of all, I really enjoyed this book. It is relatively fast-paced, entertaining and witty, thanks to the narrator. The story itself is innovative, a mix of suspense and supernatural where one does not overweight the other with a twist at the end. Furthermore, it also shows the real London, not what the popular culture portrays London, or Londoners as. You also need to appreciate all the research that must have been done into rivers and development of London through the centuries. 
 I do have to add one thing- you can see that the book is very visual- as a tv series- and I am not surprised that so many books appeared afterwards.