IN THE summer of 1939, a few short weeks before Hitler's invasion of Poland, Harvard historian William L. Langer was preparing to leave for a year's study in Mexico and Central America when he was contacted by the University Librarian, Keyes DeWitt Metcalf. Metcalf was anxious to purchase for Harvard the personal papers of a Russian exile then living in Mexico, and he asked Langer to represent Harvard in the negotiations.

On his arrival in Mexico City Langer travelled by taxi to the suburb of Coyoacan. After riding down a respectable road the taxi turned into a deserted, unpaved street, with many rust but no houses. At the end of the street was a villa, protected by walls and heavilyarmed guards. The guards had been notified of Langer's arrival and he was admitted, without too much difficulty, to the simply-furnished villa.

Langer's host was Lev Davidovich Bronstein who had been banished from Russia in 1929, and who, in the following years, was hounded-from Turkey to France and Norway and eventually to Mexico. Surrounded by a rapidly diminishing number of friends, most of his offspring and closest associates already dead, Bronstein had lost little of the intensity and dynamism which had characterized his years of greatness.

Just 20 years before, known to the world as Leon Trotsky, he had been the second most powerful man in Soviet Russia and Lenin's obvious successor. At the age of 26 Trotsky had been the undisputed leader of the abortive revolution of 1905. In 1917 he returned to Russia from exile and he planned and led the successful Bolshevik insurrection of October. He served as Commissar of Foreign Affairs and than as Commissar of War. He created the Red Army and he defeated the forces of the counter-revolution in Russia's three year Civil War.

A brilliant orator and military strategist, as well as an outstanding literary critic, Trotsky was out-foxed and out-maneuvered by Joseph Stalin in the leadership struggle which followed Lenin's death in 1924. By 1929, after five years of setbacks and humiliation, he was banished forever from Russia.

Stalin did not permit Trotsky to take all of his personal papers with him to his place of exile in Turkey, but he did allow him to take typed copies of those he left behind. By the time Trotsky arrived in Mexico in January, 1937, his papers numbered in the thousands. Each time he was forced to leave a country and find sanctuary elsewhere the papers had been packed in crates and carefully protected from theft.

And there was good reason for the careful protection. The papers were an invaluable source of documents and letters relating to the history of Soviet Russia and the men who made the revolution. Many of these documents clearly refuted the pro-Stalinist explanations of Russian history which were the product of what Trotsky called the "Stalin School of Falsification."

Stalin's henchmen made many attempts to seize or destroy the papers. One of their most spectacular--and successful--sallies occurred in November, 1936. At that time Trotsky was under house arrest in Norway, but many of the papers were hidden in a Paris apartment, supposedly out of the reach of Stalin. Nevertheless, agents of the G.P.U. (Russia's secret police at that time) located the apartment, perhaps with the aid of an agent provacateur, and they occupied the adjacent room. Then, with a torch, they cut through the intervening wall and made off with the papers.

By 1939 Trotsky was becoming increasingly apprehensive about the safety of his papers and he resolved to sell them to some library that could guarantee their safety. In his negotiations with Langer, Trotsky was especially anxious to know what protection the papers would receive, and what sort of control he could exercise over their use. Langer was authorized to spend up to $10,000 for the papers, but the main issue was not the total amount, but rather how much of the archives should be included for that amount.

Nearly 30 years Later Langer recalls his encounter with Trotsky as one of the most unfortgettable experiences of his life. He describes Trotsky as a most attractive personality, whose magnetic leadership was still evident many years after his fall from power. Following two afternoons of negotiations Langer left Trotsky, having secured for Harvard the great bulk of Trotsky's personal papers covering the years 1917 to January 1, 1937 (Trotsky required the post-1937 papers for his working archive).

Once again the papers were packed in crates and prepared for shipment, this time to their final resting place at Harvard. But not until August 20, 1940 did the papers, under armed guard, reach Cambridge. On their arrival library officials immediately telephoned Langer, who was then vacationing at Gloucester, and asked him, to come to Cambridge to inspect the documents. They also despatched a telegram to Trotsky informing him of the safe arrival of his archives.

In the preceding months Trotsky had been deserted and renounced by some of his closest associates, including his Mexican protector and benefactor, the painter Diego Rivera. And in May, 1940, Trotsky's home was subjected to an armed-raid, apparently at the instigation of Joseph Stalin. Around 4 a.m. a group of assailants broke into Trotsky's home and pumped about 200 machine gun bullets into Trotsky's bedroom. Although the attack left him miraculously unharmed Trotsky became increasingly concerned about his own safety and the safety of his papers.

After months of anxiety the telegram from Harvard must have been a great relief. Ironically, that same day, the very day he learned that his papers would be preserved and protected, Trotsky was assassinated. A man calling himself Frank Jacson, who had connived his way into Trotsky's confidence, crept up behind him while he was at work in his study, and crushed his skull with an ice axe.

AMID the fury of the Battle of Britain the death of Leon Trotsky went largely unnoticed. But not in Cambridge, nor in Gloucester where William Langer first learned of Trotsky's death.

In the weeks following the assassination, Trotsky's widow, Natalya Sedova, collected the remainder of Trotsky's papers an dsuch memorabilia as his passport and Mexican identification card and had them shipped to Harvard. In 1953 another four or five items, including Trotsky's diary, were sold to Harvard by Sedova. But the growth of the Trotsky archives did not stop even there. Some of the papers which had never been sent on to Mexico were hidden from the Germans in France during the war by the family of John van Heijenoort, Trotsky's secretary for more than 10 years. In the late 1950's van Heijenoort, now a professor of Philosophy at Brandeis and special bibliographer for Harvard's library, returned to Europe and prepared the documents for shipment to Cambridge.