I''ve written three more books: The Presence of the Past , which expands the idea of memory in nature; The Rebirth of Nature , which shows how we can once again think of nature as alive instead of inanimate and mechanical; and Seven Experiments That Could Change the World , which is subtitled A Do-It-Yourself Guide to Revolutionary Science . In the latter I focus on areas where simple, inexpensive research can make a big difference. I think that only by re-empowering independent investigation in science can the spirit of inquiry be revitalized. Science in the past was done mainly by amateurs. It has now become exclusively professionalized, but it doesn't have to be that way.