“I promise you four papers,” the young patent examiner wrote to his friend. This letter would convey one of the most important news in the history of science, but its weighty character was hidden behind the playful tone, a typical feature of its author. He had just addressed his friend, calling him a “frozen whale,” and apologized for writing a letter full of “insignificant chatter.” Only when he reached the point where he described the papers he had written in his free time did he give some indication that he understood their significance.

“The first concerns radiation and the energy properties of light and is very revolutionary,” he explained. It was indeed revolutionary. It argued that light can be considered not only as a wave but also as a stream of tiny particles called quanta. The consequences that would eventually arise from this theory—a universe without strict causality or certainty—troubled him throughout the rest of his life.

“The second paper is a determination of the true size of atoms.” Although the very existence of atoms was still in question, this was the simplest of his papers and therefore he considered it the safest choice for his last attempt to earn a doctorate. Einstein had begun a path that would revolutionize physics, but he had repeatedly encountered obstacles in his efforts to secure an academic position or even to obtain a doctorate, through which he hoped to be promoted from a third-class examiner to a second-class examiner at the Patent Office.