I'm having a ball reading classic mysteries now released as ebooks from Langtail Press and in pbook from Rue Morgue press.
John Dickson Carr (aka Carter Dickson) really did cover the entire breadth of "locked room mysteries" and "impossible murders" - sometimes going to great extremes to explain the inexplicable. The solution to the murder in "The Crooked Hinge" is the most extreme attempt yet to explain how a man could be murdered in plain view of witnesses - none of whom saw the murderer.
I shall continue on, with a liberal helping of Nero Wolfe to add spice to this heady experience.