EINSTEIN, Albert (1879-1955). Typed letter signed ("A. Einstein") to Dr. Gustaf Stromberg of the Mount Wilson Observatory, [Princeton], 19 December 1938.

In German. One page, 211 x 280mm. (mailing folds impacting signature, some scuff marks at bottom edge, unintrusive of text.)

Einstein permits Dr. Stromberg to quote him in a publication, adding: "I am pleased that you are having success with your work.". Gustaf Stromberg's astronomical work emphasized the studies of star velocities, and his work in the 1920s was critical to discovering the rate at which the solar system orbits the center of the galaxy.

Alongside astronomy, Stromberg took great interest in the non-physical world and the soul, making him a pioneer of the study of the paranormal. One year after this letter was written, Stromberg would write "The Soul of the Universe;" which utilized quantum theory, Einstein's theory of relativity, and other concepts to support the existence of a soul and the immortality of human memory. In this book's introduction, Stromberg thanks Einstein for his "encouragement and constructive criticism, which caused me to analyze more certain parts...". While Einstein did not agree with all of the book's theories, he did endorse the work, stating of Stromberg: "Very few men could of their own knowledge present the material as clearly and concisely as he has succeeded in doing."