Things to like about this book: 
 - Beautiful descriptions of London; 
 - Interesting idea about London being filled with many magical creatures; 
 - English humour; 
 - Well-written dialogues; 
 - Thomas Nightingale. The only intriguing character in the whole book. 
 Things that could be better: 
 - I didn't get attached to any of the characters and that's the main reason for me that this book had no heart. 
 - Too many characters and too many 'magical' aspects are left unexplained. Also, most of the time it's very hard to understand how Peter Grant reaches conclusions in his investigations. His thoughts and reasoning are often tangled and rushed. 
 - Maybe I'm dumb, but I didn't understand the connection between Rivers of London and Henry Pyke/Mr Punch. 
 I didn't regret reading this story, but, unfortunately, I have no urge to read the rest of the series.