Typed Letter Signed by Einstein
EINSTEIN, Albert. Typed Letter Signed. Princeton, New Jersey , 1952.
This 1952 typed letter signed by Einstein is to Daniel Lipkin, an engineer and a former student of his friend David Bohm at Princeton regarding some equations he had sent to Einstein for comment.

"Mr. Daniel M. Lipkin 4925 Rubicam Street Philadelphia, 44, Pa.

Dear Mr. Lipkin:

The possibility of this choice of coordinate system is quite obvious and generally known. It is, however, an incomplete determination fixing only 1 of the 4 arbitrary functions.

For developing the theory generally it seems to me better not to specialize the coordinate system at all. Sincerely yours, A. Einstein Albert Einstein"

"Daniel Lipkin, a Bronx, New York native, who as a self-described "awestruck 15 year-old high school student," first wrote to Einstein in 1944 and continued his correspondence with the physicist after completing his studies at Princeton (1946-1949) under Einstein's friend David Bohm. Lipkin went on to work as an electrical engineer working for Sperry Univac designing early computers, and later at American Electronic Laboratories. (Lipkin, letter to the editor, American Journal of Physics, 1981, p. 619; Obit., Philadelphia Inquirer, 29 June 2009)." (From Christie's).

HBS # 68216 $8,500