Guidelines
In addition to meeting for dinners and helping each other with technical aspects in their individual writings, the members of the club agreed to adhere to a code of ethics in their writing to give the reader a fair chance at guessing the guilty party. These fair-play "rules" were summarised by one of the members, Ronald Knox, in an introduction to an anthology of detective stories. They were never intended as more than guidelines, and not all the members took them seriously. See history of crime fiction for details. The first American member (though then living in the UK) was John Dickson Carr, elected in 1936.
The club continues to exist, although the fair-play rules have been considerably relaxed.
A number of works were published under the club's sponsorship; most of these were written by multiple members of the club, each contributing one or more chapters in turn. In the case of The Floating Admiral, each author also provided a sealed "solution" to the mystery as he or she had written it, including the previous chapters. This was done to prevent a writer from adding impossible complications with no reasonable solution in mind. The various partial solutions were published as part of the final book.
Read more about this topic: Detection Club