A book collector and Harvard Law School (HLS) graduate has given the Law School nearly 1000 rare books, including many which form the canon of Anglo-American legal thought.

Notable in the collection are the first editions of Thomas Hobbes' Leviathan, John Locke's Essay Concerning Human Understanding, and Blackstone's Commentaries.

It also includes the first legal book ever printed in England The Abridgement of Statutes, and a 1320 manuscript entitled Magna Charta cum Statutis-a medieval lawyers' manual comprised of the Magna Charta and related legal statutes.

The collection, given by the late Henry N. Ess, a 1944 HLS graduate, spans 400 years of legal writing in England.

"This gift consolidates Harvard's law library as the greatest in the world," said visiting professor Daniel Coquillette, the institutional historian at HLS.

Coquillette said the books comprise "the heart of what is meant by the rule of law." A comparable gift, he said, would be "if someone gave all the Vermeers in existence to one art collection."

According to Coquillette, the donated books give content to phrases such as "due process" and "equal protection" that are enshrined in American jurisprudence.

The books are on display at the Langdell Library at HLS. Despite their age, Coquillette said the books are in "superb" condition.