Knight, Devin: Retro Gravity And Other Self Levitations ©2011 Devin Knight Softcover, comb-bound, 8.5x11", 34 pages

Image courtesy eBay seller CosanostraMagic

Comments: Retro-Gravity allows you to levitate 2 to 4 inches in the air, is worn in your shoe, and is invisible.

Contents (from book ToC):

9 Introduction
10 My Early Levitations
10 The Meditation Mat Levitation
13 RetroGravity
15 Gimmicking The Basic Shoe (Gimmick # I)
19 Gimmicking Two Basic Shoes
20 Gimmicking The Left Shoe With A SplitHeel (Gimmick #2)
21 New Variation On The SplitHeel (Gimmick #3)
21 How To Gimmick Dress Shoes
22 Afterthoughts On Gimmicking The Shoes
23 Levitating Using One Basic Shoe
23 Three Ways To Secretly Fold Your Heel
26 The Proper Way To Levitate Up and Dow n
27 Creating The Illusion Of Floating Higher
28 The Issue of Balance
29 Swiveling In The Air
29 Lifting Both Feet W hile Le\ itating
31 The Dangling Foot
31 Advanced TechniquesShooting Up 4 Inches
32 Passing An Object Under Your Feet
33 The Invisible Force 2