Born in the Ukrainian city of Ternopil (part of Austria-Hungary in 1895), Rathaus began composing at an early age, beginning his studies in 1913/1914 at the Academy of Performing Arts and Music in Vienna.
Handwritten manuscripts, published works, and correspondence to and from Rathaus are available for research at the Queens College Special Collections and Archives.
However, as Michael Haas has pointed out, Rathaus mostly lost the artist prestige and reputation he had enjoyed in Berlin between the wars.
He took the low-paid position at Queens College to escape the threat of war, and in 1940 his worldly possessions, still in London, were destroyed by a V2 bomb.
He "never spoke of his past to any of his students, and avoided contact with former colleagues and friends who were successfully conducting concerts and opera performances in nearby Manhattan".