This book focuses on the life and work of Nathan Zuntz (1847-1920), a German physiologist, who made significant contributions to high altitude physiology and aviation medicine. He achieved fame for his invention of the Zuntz-Geppert respiratory apparatus in 1886 and the first treadmill (Laufband) in 1889. He also invented an X-ray apparatus to observe cardiac changes during exercise and constructed a climate chamber to study exercise under varying and sometimes extreme climates.