1921, Publisher A.P. Felsman, Chicago. Binding separated from covers, boards frayed. While this book is just in fair condition, it is signed by A.M. Wilson, the editor of the Sphinx and there is an inlaid letter signed by Downs on the back of a Down’s advertisement from 1910. He ends the letter by writing, “But what the armatures don’t understand is this = WHEN THE SECRET OF A TRICK BECOMES COMMON (KNOWN) ITS VALUE IS ‘GONE’.”