Hummer, Bob: A Pair From Hummer ©Unknown, Bob Hummer Softcover, comb-bound, 8.5x11"

Image courtesy eBay seller CosanostraMagic

Comments: Two mathematical effects. These have also appeared in Hummer's "Collected Secrets", edited by Karl Fulves.

Contents (from cover, numbers are not page numbers):

1 The Whispering Spirit: Mental divination of how many cards were cut from the deck
2 Hummer's Fantastric: card revelation with a borrowed deck, and most of the work is done with the magician's back turned