This book, long out of print, is still THE monograph about rubber.
It goes over my head in many ways, but my physicist brother will explain the "mystical" parts, hopefully.
I paid about 7 Euros for it, plus P+P. It came from the library of a college in London. The library reg card is still in it. It has been issued about 55 times in roughly 35 years, and must have been read countless times in the library itself.
I love old books like this, especially when they deal with slingshot related stuff :)
What piqued my interest was Treloar's chapter regarding the swelling effect of rubber soaked in certain liquids - they obviously change their nature when "swolen". Will it improve power, stretch, speed? I have to find out.