“HOW COULD YOU have been such a jerk?” This question, directed at Harry Gold by his younger brother, is quoted almost exactly at the mid-point of Allen M. Hornblum’s “The Invisible Harry Gold.” The question in fact is the very essence of the book, the engine of its inquiry, the propulsive energy pressing forward its relentless research. How Harry Gold could have been such a jerk is a profound question, and Hornblum does a highly commendable job of answering it.Gold is one of the least known, least remembered and least understood members of the spy ring that conveyed to the Soviets the secrets of America’s atom bomb in the late 1940s and early 1950s. No doubt as more classified documents from US government agencies and from KGB files continue to be made public, more will be learned about Julius and Ethel Rosenberg, David Greenglass, Morton Sobell, Klaus Fuchs and others. The final word will likely never be written about these figures; every few years new interpretations regarding the “atom spies” come tumbling off the presses. But regarding Harry Gold at least, we now have about as complete a picture as one could hope for.Hornblum, an independent scholar, has done exhaustive research, as evidenced by his notes and bibliographies. But he was also helped in no small measure by the fact that Gold, alone among the spies, immediately pleaded guilty, cooperated completely with the FBI, documented in great detail all of his espionage activities and readily testified against his co-conspirators. That testimony was crucial, as the government case against most of the other spies was fairly thin and circumstantial. To further confound matters, although Gold evidently transferred more classified US documents into the hands of Russian secret agents than did any other American, he himself was never a member of the Communist Party.It was Gold’s confessions and wholehearted cooperation with investigators and prosecutors that made him a reviled figure among the other spies and their defenders. Gold was also especially demonized among revisionist historians like Walter and Miriam Schneir, who in “Invitation to an Inquest” (1965) maintained that the spies were not spies at all but rather innocent victims of a vast FBI conspiracy spearheaded by the pathological liar Harry Gold.Hornblum argues convincingly that Harry Gold had an unusually conflicted character and that while a secret agent he lied as a matter of course. But when Gold finally came clean, Hornblum maintains, he really did come clean. He did so furthermore with no expectation of leniency and in no effort to cut a deal with the authorities. The evidence is abundant that Gold sincerely believed he had committed what he termed “a horrible mistake,” that he wished somehow to make up for it, and accordingly that he was ready to pay the price for his misdeeds against the United States, a nation that he insisted he loved and had never wished to harm.SO WHO WAS THIS PERPLEXING individual? He was born Heinrich Golodnitsky in 1910 in Switzerland to Russian Jewish parents who soon emigrated to the US. The family settled in South Philadelphia where they experienced poverty and anti-Semitism. His father was a humble cabinet maker and follower of Tolstoyan ideals, his mother a neighborhood teacher of Hebrew and Yiddish. By all accounts Harry was a studious, meek little fellow who constantly helped other kids with their homework. He was also the kind of schnook who could never deny a request for a loan – even if he had to borrow money to help others. Short and overweight, he was easily bullied and evidently could never say no to any demand, attributes that would prove valuable to his future Soviet handlers.Gold aspired to a career in science but could not afford to go to college. He found work in a science lab, labored like a demon (something he would do for the rest of his life), saved enough to enter the University of Pennsylvania, but soon had to drop out when his father lost his job in the Depression. Harry became the main breadwinner for his family, took courses at night and, although he was no student of politics or economics, became convinced that the Soviet Union held out the greatest hope against the evils of capitalism and anti-Semitism. It wasn’t long before certain acquaintances suggested that the Soviet people would benefit from the knowledge of industrial chemical processes of the sort being used by Gold’s employer and that were denied the Russians by the US government. Gold thought such assistance made sense. The Soviet Union, he told himself, was after all an ally of the United States (not that that made any difference under the law). Besides, he was the boy who couldn’t help helping others. Thus began years of Gold’s conveying to his Soviet contacts mountains of American scientific documents, from material regarding processing alcohol from sugar to film development techniques at the Kodak labs in Rochester to the design of atom bombs at Los Alamos. Gold never asked for or expected to be paid for his work, although he was reimbursed for a portion of his travel expenses. He also gratefully accepted a lump sum that helped him get a degree from a university in Ohio, where the Soviets had him gathering classified material from a major US Air Force base in Dayton. The Soviets also honored him with the Order of the Red Star.When Klaus Fuchs, a diehard Communist, was finally nailed as the Manhattan Project scientist who provided the Soviets with the secrets of the Bomb, the search was on for his contacts. Fuchs never even knew the real name of the short, dumpy man to whom he had turned over his documents, but the FBI eventually found him. Gold, as noted, confessed, cooperated, named all the names he knew and testified against his co-conspirators. Not that this did him any good in the eyes of the law. He received a sentence of 30 years, twice the sentence meted out to Fuchs (and Fuchs was released after nine years). Gold’s sentence was even longer than what his prosecutors had sought.Gold didn’t utter a peep of protest. Off he went to a maximum security prison, where he got assigned to the facility’s hospital, conducted valuable medical research (he eventually earned a patent for a medical device), always worked overtime and became a leader of the services for the prison’s Jewish inmates. He also repeatedly volunteered to undergo medical experiments, and in one hepatitis trial he apparently suffered serious damage to his health. It seems the only reason he even sought parole was so that he could be of assistance to his aged father.Released after 16 years, Gold found work at a hospital lab in Philadelphia where he did much valuable work. He was deeply admired by his co-workers, as he had been by his fellow prisoners, by the prison staff and by the two court-appointed lawyers (one a former national chairman of the Republican Party) who served him, unpaid, for over 20 years. After six years of freedom, however, Harry was diagnosed with a faulty heart valve. He elected to undergo open heart surgery, which in 1972 was a risky operation. Gold died, aged 61, on the operating table.Thus ended the fascinating career of a bland little cipher brought very much to life by Hornblum’s dogged research. Indeed, Hornblum seems to have left no fact unturned – and a great many are reported more than once in his book. “The Invisible Harry Gold” also has some visible slips, like spelling Rosenberg lawyer Manny Bloch’s name differently in two consecutive sentences, or omitting some quoted sources from his bibliography.No matter; this is one riveting biography. Harry Gold was indeed something of a jerk. But even some jerks merit some sympathy.