Mystery of hound with curtailed barking (8)
I believe the answer is:
whodunit
'mystery' is the definition.
(I know that mystery can be written as whodunit)
'hound with curtailed barking' is the wordplay.
'curtailed' means to remove the last letter.
'barking' indicates anagramming the letters (UK slang for mad).
'hound'+'with'='houndwith'
'houndwith' with its final letter taken away is 'houndwit'.
'houndwit' anagrammed gives 'WHODUNIT'.
'of' is the link.
(Other definitions for whodunit that I've seen before include "'A crime novel, colloquially (8)'" , "Murderer revealed at the end, US style" , "Crime story (colloq.)" , "American-style murder story" , "Question commonly posed" .)