Would you like some help understanding the beginnings of the detective genre? The Sign of Four is one of the earliest detective mystery novels and had significant impact on the genre. This guide will allow you to understand the development of the detective genre and details the historical background to the story. It offers chapter-by-chapter commentary and guiding questions, also a concluding analysis of the text. Graphic organizers allow the reader to make concise notes on Holmes' scientific method of solving a case.