String Sounds (1968)
Discusses the principles of sound production in string instruments, highlighting how the tension and length of strings affect pitch. Tighter and shorter strings produce higher sounds, while longer strings create lower sounds. The interaction between the strings and surrounding materials, such as walls or wooden boxes, can amplify sound. The text also touches on the need for tuning due to loosening from play and mentions various cultural string instruments, such as the Japanese koto and the Indian sitar, emphasizing the unique sounds of each. Additionally, it briefly references American mountain music and the collaborative nature of playing stringed instruments.