I've just completed a 10,000 word dissertation for a professional diploma in sound therapy. This included spending a year researching using sound therapy to help people suffering from insomnia. Patricia Morrisroe's book was the single most useful resource I had. Not only is it a fascinating and engaging read, it's also chock full of references to scientific research (with the academic references to follow up for oneself if desired) that tell the wider story of sleep and many different ideas about how to deal with insomnia. Highly recommended!