Rivers of London, by Ben Aaronovitch

A fun police detective book.

This was very fun! Also very on-point about British class distinctions! I don't want to spoil anything, if you're looking for a fun and unexpected detective story, this is it.

I really want to write a mystery/detective novel? But I don't want it to be yet-another "police detective or doctor detective" novel? Also it should call on my very specific knowledge and expertise of a particular profession/world which is somehow very relevant to detecting but which hasn't really been used before. But I don't have any knowledge/expertise of any particular professions/worlds, let alone relevant ones -- nominations for professions that I could learn in order to then write a mystery about them on the back of a postcard please.