I loved this book. Comparisons to Jonathan Strange & Mr Norell aren't so far amiss, except this book can be devoured in a weekend, and probably should be read in as few sittings as possible. Whereas JS took me over a year and can be used as a doorstop in between sessions. 

Lucia Graves' translation is plain brilliant; this book is thoughtful, horrific and frequently chortle-out-loud funny.