Like The Mystery of the Yellow Room, The Secret of the Night is a Joseph Rouletabille mystery. In The Mystery of the Yellow Room fictional detective Rouletabille investigated a complex and seemingly impossible crime - in which the criminal appears to disappear from a locked room! There've been so many locked-room mysteries since that it's become a subgenre - but there are folks who believe Gaston Leroux invented the form. (We hate assertions like that. Have you noticed how often things turn out to have been invented by monks in the middle ages, or by prehistoric Chinamen, or seventeenth-century Englishmen? - Heavy sigh.) John Dickson Carr, the master of locked-room mystery, named The Mystery of the Yellow Room as the "finest locked room tale ever written" in his 1935 novel the Hollow Man.
