In his theory of special relativity: There are many good popular books describing special and general relativity. Two that I found particularly engaging are Kaku 2004 and Galison 2003. Reading Einstein 2005 is always rewarding. In Tyson’s witty 2007 collection of essays, he tackles many related topics beautifully.

even for relative speeds as low: Chou, Hume, Rosenband, and Wineland 2010.

The theory was based largely: Einstein himself explained the principles in Einstein 1955. Hawking 2007 presents a collection of Einstein’s papers. In the scientific biography of Einstein, Pais 1982 explains the principles beautifully. Greene 2004 puts the theory in layperson’s terms in the context of modern developments.

“If a person falls freely”: The Kyoto Lecture was delivered on December 14, 1922. It was translated into English by Y. A. Ono, from notes taken by Yon Ishiwara (Physics Today, August 1932).

the deviations recorded by his team: The results were described in Dyson, Eddington, and Davidson 1920.