In How To Sing, originally published in 1902, German opera superstar Lilli Lehmann gives a technical guide to vocal skills. She set out to study the phenomenon of singing by exploring the expressions' singing open,' 'covered,' 'dark,' 'nasal,' 'in the head,' or 'in the neck,' 'forward' or 'back.' But the book turned into something more and transformed into the guide of guide to thinking musically and a dimensional meditation on the general art of learning.