Galen Joseph-Hunter talks with Douglas Kahn, author of "Earth Sound Earth Signal." The book is a study of energies in aesthetics and the arts, from the birth of modern communications in the nineteenth century to the global transmissions of the present day. Douglas Kahn begins by evoking the Aeolian sphere music that Henry David Thoreau heard blowing along telegraph lines and the Aelectrosonic sounds of natural radio that Thomas Watson heard through the first telephone; he then traces the histories of science, media, music, and the arts to the 1960s and beyond. Earth Sound Earth Signal rethinks energy at a global scale, from brainwaves to outer space, through detailed discussions of musicians, artists and scientists such as Alvin Lucier, Edmond Dewan, Pauline Oliveros, John Cage, James Turrell, Robert Barry, Joyce Hinterding, and many others.