Clue: Naturalised American – Vladimir, initially – harbouring troublesome book? (7)
Answer: NABOKOV
Explanation: Naturalised American – Vladimir, initially – harbouring troublesome book? (7)
An envelope ('harbouring') of BOKO, an anagram ('troublesome') of 'book' in N A V ('**N**aturalised **A**merican **V**ladimir initially'), with a splendid &lit definition, with the 'book' being *Lolita*.