Corinda, Tony: The Powers of Darkness ©1975 Magic, Inc., Chicago, IL Softcover, saddle-stitched, 5.5x8.5", 11 pages

Image courtesy eBay seller Tarrfether

Comments: a unique experiment in sensory perception with the spectator's eyes closed, using two rings from a Linking Ring set, 10 inches or larger.

Contents (from book):

2 Introduction: presented as an experiment in psychology, not a magic trick
3 The Routine
4 Preparation: a chair with a cushion, the rings, a pencil
4 Part I - The Ring Goes On
6 Part II - The Ring Comes Off
9 Short Sequence (Jay Marshall): addition to the routine suggested by Billy McComb