J. S. Fletcher 
The Orange-Yellow Diamond [EPUB ebook] 

The orange-yellow diamond is written by J. S. Fletcher. This murder mystery from the 1920s, which is set in London, pulls off the amazing feat of being both incredibly racist and impressively diverse. On the one hand, a terrific lower-class Jewish amateur detective is the unquestionable hero and intellectual center of the whole thing and stars in the happy ending; on the other, Horrendous Stereotype Klaxon. All which said, this book features a London full of thriving immigrants (Maltese, Scots, Burmese, Japanese, and South Africans, many of them not actually murderers despite the book's high body count) is actually much more offensive than modern historical that present London as all-white and predominantly upper class plus servants. In a parallelogram formed by Oxford and Cambridge Terrace on the south, Praed Street on the north, Edgware Road on the east, and Spring Street on the west lie a collection of mean streets on the southern edge of the populous parish of Paddington. The drab dullness of these streets stands in striking contrast to the pretentious architectural grandeurs of Sussex Square and Lancaster Gate, which are nearby. The keen observer will always notice in these streets all those indications of the gloomy semi-poverty that are more pronounced in London than in any other English metropolis.