A Svengali deck is a trick deck of cards that allow for the performance of a range of tricks--included are a series of duplicate cards, in this case aces of hearts, that are cut slightly shorter than the rest. As such, when arranged with an Ace placed behind each "regular" card, the aces will skip one's thumb when riffling through the deck, but anywhere that a spectator cuts the deck can be made to reveal an Ace.) This is a rare deck (I can find no others out there anywhere) produced by Superior Magic Company of Cleveland, Ohio, copyright 1936. The double sided tri-fold set of instructions wrapping them include  not just an explanation of various tricks that can be performed with them, but also accompanying (pretty silly) "patter." Fun for everyone!!!!