Jacob Shatzky was one of the new generation of Polish Jewish historians who grew to maturity during the interwar decades and were virtually wiped out during the Second World War. It was Shatzky's fate to survive the Catastrophe. During more than forty years of literary activity, he produced hundreds of articles, critical reviews, monographs and booklength studies, in addition to editing numerous anthologies and annuals. His writing ranged .over the length and breadth of modem Jewish history and thought, from Spinoza to Yiddish theatre and literature, from the Jewries of Central and Western Europe to the new communities in Latin America and the United States. His best and most important works focused on the Jews of Poland, Lithuania and the Ukraine, the constituent parts of Old Poland. Shatzky's name was inextricably linked with that of the YIVO Institute for Jewish Research, whose American branch he cofounded.

The future historian of Warsaw Jewry was born in the Polish capital in August 1893 to Bezalel and Eide! Shatzkin, neither of whom was a Warsaw native. Shatzky's father was a Litvak from Biafystok, who was a supplier to Russian military and administrative installations in and around Warsaw. Shatzky's mother came from Berdichev in Volynia and was her husband's second wife. She kept a kosher, though not especially religious, home for her spouse and his children by her and by his first wife. Bezalel Shatzkin was a maskil interested in secular culture, to which his family was exposed in what Jacob Shatzky later recalled as ‘an aristocratic Polish neighbourhood … certainly not in a Jewish area … usually among gentiles - mostly Russian officers and bureaucrats on account of my father's livelihood …’ .

Jacob received his first formal education at a traditional Jewish heder. His first contacts with the history of Warsaw Jewry came during the funerals of great Jews, when he would accompany his father, who believed 'that a person feels life when he goes to give honour to the dead.' His son would later reflect that: