The Talmud, the 63-volume record of discussions among rabbis that is one of the most sacred books in Judaism, has lacked a comprehensive index for 1,500 years -- until now.

A US-based Jewish publisher has produced an alphabetical index to the Talmud Bavli (Babylonian Talmud), a work it describes as "a groundbreaking literary achievement."

The multi-volume Talmud was made to be transmitted orally and has no punctuation or paragraphs. And while there are online sites and electronic methods to search the labyrinthine work, most are difficult to operate or too expensive to use.

Enter the "HaMafteach" ("The Key"), a new indexed reference guide to the Talmud Bavli.

Surprisingly, the author is not a learned rabbi, but rather 63 year-old Jewish immigration lawyer Daniel Retter.

Retter, who moved to New York when he was a child with his parents who escaped the Holocaust, said it took him seven years to complete the work.

"I could not understand why the Talmud did not have an index," he recently told The New York Times. "I'm a lawyer, and if I want to know the law, I look it up in an index."

"So many volumes, so many topics, so many Sages' sayings, exchanges and expressions," New York-based Feldheim Publishers said about the so-called "Sea of Talmud."

"But here is a tool which allows you to navigate the entire length and breadth of the Talmud and locate specific source material with ease."

The HaMafteach has some 6,600 major subject entries, 27,000 sub-entries and 42,000 Talmudic reference sources, according to Feldheim.

There are two versions of the Talmud: the Babylon version and the Jerusalem Talmud (Talmud Yerushalmi), both of which were compiled around the year 540. The first print editions appeared in Europe in the 16th century.

The HaMafteach sells for $30 in English and $25 in Hebrew.