Godwin is famous for two books that he published within the space of a year : An Enquiry Concerning Political Justice , an attack on political institutions , and Things as They Are or The Adventures of Caleb Williams , which attacks aristocratic privilege , but also is virtually the first mystery novel . Godwin is most famous for two books that he published within the space of a year : An Enquiry Concerning Political Justice , an attack on political institutions , and Things as They Are ; or , The Adventures of Caleb Williams , which attacks aristocratic privilege , but also is virtually the first mystery novel .