Sherlock Holmes was one prescient fictional detective. Long before law enforcement officers started using advanced crime-solving techniques like forensic chemistry and fingerprint analysis, Sir Arthur Conan Doyle’s iconic sleuth employed these practices in novels like 1887's A Study in Scarlet and 1890's The Sign of the Four. Ad Week recently ran this infographic by publisher Quirk Books that lists some of the surprisingly sophisticated scientific methods Holmes used to crack his cases. Check them out below.

[h/t Ad Week]