I do enjoy the technique of writing the story as though it is a manuscript from the past, including footnotes. We are looking at the beginning of the twentieth century from many centuries in the future.
London tells the story of Ernest Everhard and the revolutionists fight for justice for the common labourer. It is about the class struggle and conflict of interest between labour and capital.
The extremely abrupt ending is frustrating but also ensures that the reader will continue to ponder the story well after finishing it in an attempt to create their own ending.