The warm weather hasn’t stopped the wind from blowing or the foliage from turning gold and red and orange. As the leaves fall, and the trick-or-treaters prepare to make their rounds, here in Baltimore it’s also “Pumpkin Papers” season. Recalling this fascinating chapter of the Cold War is as much a part of an anticommunist’s autumn as little kids dressed like ghosts or storefronts decorated with dried cornstalks and hay bales.

There’s an annual Halloween dinner in Washington centered on the Pumpkin Papers and the spy case of Whittaker Chambers and Alger Hiss: Chambers, the journalist, Maryland dairy farmer, and ex-Bolshevik who was dismissed by Establishment liberals as a liar; and Hiss, the man now known to have spied for the Soviet Union though he protested his innocence until the day he died.

We who are aficionados of “The Case” can tick off its many colorful and quirky features—the Bokhara rugs, the sighting of a rare species of bird (the prothonotary warbler), the Ford Model A Roadster with the “sassy” trunk, the Woodstock typewriter. One feature that’s not just memorable but downright outlandish is the concealment of microfilm in a hollowed out pumpkin on a farm near Westminster, Maryland.

It’s quite a story.

In the summer of 1948, Alger Hiss sued Whittaker Chambers for libel after Chambers went on a radio program and reiterated what he had told HUAC, the House Committee on Un-American Activities: that the former State Department lawyer, Hiss, had been Chambers’ communist comrade in the 1930s. The libel suit was brought in Hiss’s hometown of Baltimore.

Watching the footage of the two men testifying on Capitol Hill is as riveting today as it ever was: Alger Hiss’s briskly professional demeanor as he issues his denials, and then the halting and emotional sentences of Whittaker Chambers, telling the congressmen,

I don’t hate Mr. Hiss. We were close friends. But we are caught in a tragedy of history. Mr. Hiss represents the concealed enemy against which we are all fighting and I am fighting. I have testified against him with remorse and pity.

Neither Hiss nor his many defenders were aware that Chambers had proof that Hiss and others working in various parts of the government had handed him documents to pass on to Soviet military intelligence.[1] Hiss believed his impressive credentials and the backing of friends in high places would enable him to discredit Chambers and make his charges go away. Indeed there were those, including many in the media, who were convinced that the communist controversy that had broken out after World War II was merely a way for conservatives and Republicans to defame New Dealers like Hiss and Harry Dexter White, a key assistant to the Secretary of the Treasury.

Innocently enough, Hiss’s attorney in the libel action, as part of the discovery process, asked the defendant to produce documents to back up what he had said about Hiss on the radio show Meet the Press. There were some, as it happened. Chambers had stashed them away, as a kind of insurance policy, when he defected from the communist underground a decade earlier.

Chambers came forth with what became known as the Baltimore Papers on November 17, 1948, after agonizing about it. The reader of Witness, his famous 1952 memoir, will learn that the angst he felt about coughing up the documents had many elements. The scorn he brought on himself and his family by being an informer pained him. Also he had been trying to avoid the specific issue of espionage in hopes that Hiss, too, might experience a change of heart and come forward voluntarily. Perhaps most vexing of all: by substantiating that confidential information was given to a foreign power, Chambers would be laying himself open to possible perjury charges. (In testimony he had given a month earlier, before a grand jury in New York, he had skirted the issue of espionage.)

The full cache had 65 typewritten summaries of State Department cables and a War Department report, along with four notes in Hiss’s handwriting, two strips of developed microfilm, three canisters of undeveloped microfilm, and a long memo in the handwriting of White, the Treasury official. Parts of the cache—everything but the developed and undeveloped microfilm—Chambers gave to the lawyers in Baltimore. These were the parts that incriminated Hiss, who was suing him, and Harry Dexter White, who was dead. (White had come before HUAC, indignantly denied being a communist, and suffered a fatal heart attack soon afterward.)

As per the judge in the libel suit, no one who wasn’t party to the suit could know about this explosive new evidence while the proceedings were ongoing. But Chambers had held back the microfilm—it came from other underground contacts in Washington, not Hiss, and so wasn’t covered by the discovery request. If he went public with it, the doubts about him would dissipate.

But he wavered. As he says in Witness, “A drowning sea of hostility, public and secret opposition, skepticism, hatred and simple lack of understanding of my purpose washed around me.” He considered retreating—committing suicide, even, and sparing his other former comrades from being exposed. “By destroying the film, I could spare these people completely,” he wrote. These others, after all, weren’t loudly denying the truth or sending lawyers, private eyes, and possibly Communist Party operatives to his farm to find ways to tear down his testimony and his reputation.

In the end, he didn’t destroy the microfilm, which held material from the Navy Bureau of Aeronautics. He gave it to HUAC’s investigators. But not before nervously leaving it behind on the farm while he had to go down to Washington. A safe place to hide it for the day would be in his and his wife’s pumpkin patch.

He picked a pumpkin, went into his kitchen, scooped out the pulp and seeds, and put in the two strips of microfilm wrapped in wax paper and the three cylinders of undeveloped microfilm. He put the top back on and placed the pumpkin back outside in the pumpkin patch. “The whole art of the concealment lay in its complete naturalness and complete unexpectedness,” he wrote. “I fought Communism precisely with those arts which Communism had taught me, and no other experience could.”

When the news got out of this unusual evidence so unusually obtained by HUAC, it caused a sensation. The Daily Worker, official newspaper of the Communist Party (for which Chambers used to work), ran articles on “the Pumpkin Hysteria,” including one headlined: “House Un-Americans Pull New ‘Spy’ Hoax Out of a Pumpkin.” The experts at Eastman Kodak, the company that made the microfilm, at first seemed to agree, declaring that the undeveloped rolls were of a kind that hadn’t yet existed when Chambers said he got them (1938). After a harrowing few days, they corrected themselves and said the product did exist in 1938. “God is against me,” Chambers remembered feeling in the interim.

Then the microfilm became the object of a battle royal between HUAC member Richard Nixon (R-Calif.) and the U.S. Department of Justice, which was supervising the grand jury probe in New York. The future President was called before the grand jury to be questioned about the microfilm, a.k.a. Pumpkin Papers, but he refused to turn the evidence over, according to historian Allen Weinstein. The grand jury voted to demand it, but Nixon and the House committee wanted to deal only with the FBI, not the Truman Justice Department. Nixon prevailed; laboratory experts at the FBI went to work examining the microfilm, which did prove to be authentic.

Hiss, meanwhile, was also being called before the New York grand jury. On several matters he strained credulity (as well as concealing evidence from the government and from his own legal team). He tried to convince the grand jurors of a frame-up, suggesting that while the Baltimore Papers may have been typed on the Hiss family typewriter, Chambers had likely gotten hold of the machine and typed them.

By this time even the Justice Department officials who joined in the grand jury investigation “had all become increasingly skeptical of Hiss’s testimony,” wrote Weinstein. Prosecutors started to direct the jurors’ attention away from Chambers and toward Hiss.

It was Hiss they ended up indicting for perjury. They had to settle for perjury because the statute of limitations on espionage had run out.

[1] Others contemporaneously confirmed Alger Hiss as a member of the Ware Group, a communist cell in Washington: Nathaniel Weyl, who was a member of the group, and a Vienna-born courier for the NKVD named Hede Massing. More confirmations of Hiss’s Ware Group membership (an issue distinct from his handing over of U.S. government documents to Russia) later came to light: from the novelist Josephine Herbst (whom Allen Weinstein describes in his 1978 book Perjury as concealing this information from everyone but the Hiss defense team) and from Noel Field, an American agent of the NKVD/KGB who disappeared behind the Iron Curtain in 1949. Chambers’ account in Witness, of Hiss’s effort in Washington in April 1936 to recruit Noel Field to work for Soviet military intelligence, in competition with Hede Massing and her husband, who were trying to recruit Field to work for the NKVD, was independently corroborated by Hungarian secret police records of the interrogation of Field in 1954 (first written about by historian Maria Schmidt, Battle of Wits: Beliefs, Ideologies, and Secret Agents in the 20th Century, 2007). Chambers’ account of the April 1936 incident is also corroborated by the notes of former KGB officer Alexander Vassiliev, who in the mid-1990s summarized KGB files of the 1930s and 1940s (John Earl Haynes, Harvey Klehr, and Alexander Vassiliev, Spies: The Rise and Fall of the KGB in America, 2009, pp. 4-12). Most recently, journalist Kati Marton, in True Believer, a biography of Field, substantiates that the April 1936 incident with Hiss took place by citing what the Massings said about it in interviews they gave to the late foreign affairs correspondent Flora Lewis.