What an absolute joy!
I'll admit, words have always been a favourite thing of mine so all the new, seldom used and oft unknown ones in this Oxford based mystery were an extra bonus.
The basic bones of the story - Years ago Martha's sister disappeared and now someone is sending mysterious riddle and word play based puzzles to her and her colleagues at the Clarendon English Dictionary suggesting they know what actually happened. . .
To be fair it took me a couple of chapters to get into the flow of the story (hence the 4 stars instead of 5) but once I hit the groove it just flew by. It may not be to everyone's taste as it gets quite wordy in places but as Dent is the lexicographer's lexicographer that's only to be expected really.
Very much recommended