The Doubles Aerial Hoop Bible (paperback) from Spin City is a reference book for aerial hoop artists training with two people on a single hoop at the same time. It is a great aid for learning aerial hoop tricks and positions and is suitable for beginners and right up to advanced aerialists.
Its 235 pages are packed with over 300 colour photographs demonstrating two person aerial hoop, aka lyra, tricks and positions. There is not too much in the way of written instruction in this book but the pictures are clear and there are plenty of them! And for the price this in one of the best value aerial hoop books around.
REMEMBER: Aerial manuals are great training aids but they are no a substitute for professional tuition. Never train by yourself and don't try new moves for the first time only using a book or video; get personal instruction and use books, DVDs and YouTube for additional tips and reminders only.