[Human]: Could you recommend similar authors to Philip Pullman [Assistant]: Sure, I can try.  First, do you like Fantasy or Children's literature books? Or perhaps Mystery or Historical Fiction best? [Human]: I like mystery books [Assistant]: So do I. Have you read any Agatha Christie.  Pullman is an English novelist and so is Christie. [Human]: Thank you for the recommendation 
You're welcome.  I hope you enjoy the books.