The phrase 'cultural phenomenon' is sometimes over-used, but its relevance to the TV series Sherlock is undeniable. Few shows have been the subject of discussion between the UK's Prime Minister and Chinese fans; few have found such a devoted fanbase almost overnight; and few have attracted hordes of viewers to watch their location filming. This is the first book to explore the hit series in relation to adaptation studies, TV aesthetics and stardom. It also delves into industry, audience and academic discussions of 'quality' TV, approaching 'quality' as a combination of emotional investments and genre-like classifications - this is drama that matters to fans, journalists, academics, producers, TV executives, social media mavens and casual viewers. The book's final part focuses on fan practices, exploring how Tumblr and the Twitter hashtag #Setlock play vital roles. Sherlock fandom is highly diverse, and Sherlock: Detecting Quality TV develops an original theory of "trans-fandom" alongside breaking new ground in "quality TV" debates.