This is beautiful.
I'm really, completely teary right now.
Read the whole thing.
"David had grown up in an atheist family in Moscow. The son of a renowned scholar of the Byzantine empire, David’s reputation as a prodigy was well known in the Boston Jewish community. He had emigrated with his young family in 1975 and joined the Harvard mathematics faculty. In 1977, he was appointed a full professor and became known for his important contributions to group theory, a cornerstone of mathematics with applications in fields such as physics, quantum theory, and computer science."
"Despite his atheist background, in his early 20s David discovered his Jewish roots, became observant, and taught himself Hebrew. He was a source of inspiration for the early refuseniks in Moscow. By the time we met, he had vast knowledge of both Hebrew and Aramaic Jewish texts. The Rav enjoyed conversing with him and was amazed by his brilliance and his dedication to Jewish studies."
"On a Sunday morning in 1977, following the Rav’s Talmud class, David approached me. “Do you want to learn together?” he asked, in a pronounced Russian accent. I said yes, and we set up a daily schedule and started studying b’chevruta, literally “in friendship,” as partners."