The Talmud is a formidable body of work: 63 volumes of rabbinical discourse and disputation that form Judaism’s central scripture after the Torah. It has been around for 1,500 years and is studied every day by tens of thousands of Jews. But trying to navigate through its coiling labyrinth can be enormously difficult because the one thing this monumental work lacks is a widely accepted and accessible index.

But now that breach has been filled, or so claims the publisher of HaMafteach, or the Key, a guide to the Talmud, available in English and Hebrew. It was compiled not by a white-bearded sage, but by a courtly, clean-shaven, tennis-playing immigration lawyer from the Bronx.

The index’s publisher, Feldheim Publishers, predicts it will be snatched up by yeshivas and libraries, but more important, it will be a tool for inveterate Talmud students — and there are plenty of those. Feldheim’s president, Yitzchak Feldheim, said the first printing of 2,000 books — a market test — sold out in a few days here and in Israel. More printings have been ordered.

The index has 6,600 topical entries and 27,000 subtopical entries that point students to the treatises and pages of text they are seeking.