Carolyn Wells 
The Technique of the Mystery Story [EPUB ebook] 

For one, I have never been one of those who apologize for my frank and never-ending delight in mystery stories. Their mazes have led me unwearied through miles of printed pages, and if only the problem has been worth while, and its pursuit has led along surprising ways, past shuddery thickets and over fearsome bridges, my soul has returned to sober affairs refreshed and content. In a word, here is a remarkable volume which shows us how the wheels go round, not by dogmatic statement, but by an amazing breadth and variety of citation and quotation, showing not only what great mystery writers have thought of their art, but illustrating by apposite examples how they secured their effects.