For an organization devoted to exposing the secrets of others, Wiki­Leaks, under the leadership of Julian Assange, has been aggressively protective of its own secrets. Now Daniel Domscheit-Berg has pulled back the curtain with a memoir about his three years as Assange’s spokesman. Although he began as an idealistic supporter of Wiki­Leaks’s whistle-blowing mission, Domscheit-Berg left the organization because he was dismayed by Assange’s paranoid resistance to transparency, lack of political neutrality, and addiction to concentrating power in his own hands — anti-democratic vices that Wiki­Leaks was founded to oppose.

A German open-source activist and network security designer, Domscheit-Berg met Assange in Berlin in 2007 and soon became his closest colleague in the small organization. He writes enthusiastically about WikiLeaks’s early whistle-blowing successes, such as its publication in 2008 of hundreds of documents from the Swiss banking house Julius Bar, exposing the tax shelters of the rich. But from the beginning, Assange and his tiny staff were unwilling or unable to review carefully the digital document dumps they received from anonymous sources and to separate genuine whistle-blowing material from private information whose disclosure had no clear public benefits. This led to privacy invasions that Domscheit-Berg laments, including the mistaken identification of a German citizen as a tax evader. Domscheit-Berg also regrets that WikiLeaks published the hacked e-mails of Sarah Palin, even though they contained private photos of her children but nothing scandalous or newsworthy. “I thought the leak of Palin’s hacked email was weak and of questionable relevance,” he writes. “We became increasingly brazen.”

Domscheit-Berg attributes Wiki­Leaks's increasing brazenness to Assange, who was more interested in attracting publicity (and women) than in making careful determinations about newsworthiness. Although he praises Assange for being “imaginative” and “energetic,” he ultimately finds him “so paranoid, so power-hungry, so megalomaniac” that he adopted the cultish secrecy, financial opacity and self-promoting marketing strategies of the people he fought against. A nomad and eccentric who wore two pairs of dirty pants and worked off a laptop while sleeping on borrowed couches, Assange was constantly fleeing from real and imagined enemies, objecting to Domscheit-Berg’s basement apartment because he feared his critics could peer through the windows. At the same time, Assange was contemptuous of his American supporters, such as the feminist Naomi Wolf and the filmmaker Michael Moore, who donated the bail money that secured his release from prison on rape charges. He ran WikiLeaks as a cult of personality, one that reminded Domscheit-Berg of the Church of Scientology, whose rituals they exposed. Although an anarchist who believed that those in power should be brought low, Assange refused to tolerate any criticism from his subordinates. Once Domscheit-Berg began to challenge him, their friendship fell apart. “Do not challenge leadership in times of crisis” became Assange’s favorite slogan.

“It was almost funny,” writes Domscheit-Berg, that Assange “had adopted the language of the powermongers he claimed to be combating.” Later, when Assange tried to kick him out of Wiki­Leaks, he gave as a reason “Disloyalty, Insubordination and Destabilization in Times of Crisis.” These concepts were taken from the Espionage Act of 1917 — the same law that the Obama administration is considering invoking to charge Assange with betraying military secrets.

Domscheit-Berg argues convincingly that Assange should not be charged under the Espionage Act he was so fond of quoting. “I am fundamentally opposed to anyone facing legal sanction for making information public,” he writes. Nevertheless, he became increasingly troubled by the hypocrisy and recklessness of Wiki­Leaks under Assange’s leadership. He worried that WikiLeaks and its media partners published the Afghan War diaries in 2010 without sufficient time or resources to engage in the “harm-minimization” procedures that Assange misleadingly promised — namely, blacking out names to protect innocent Afghans. Domscheit-Berg was concerned about growing criticism that all of WikiLeaks’s major publications in 2010 were aimed at its “only enemy,” the United States — mostly because focusing on a less visible adversary “wouldn’t have gotten [Assange] on the nightly news.” He was appalled when Assange floated the idea of getting paid directly for leaked documents by auctioning off exclusive access to the highest bidder — “a kind of eBay for Wiki­Leaks”— and repeatedly refused to make WikiLeaks finances transparent. And Domscheit-Berg was disturbed when Assange alone decided which leaks would be published and which would languish in obscurity — and when he made decisions not on the basis of content or newsworthiness but as part of his personal campaign for global celebrity.

To maintain the benefits of Wiki­Leaks and avoid its many shortcomings, Domscheit-Berg and another disaffected colleague have started a new platform that they call OpenLeaks. Their goal is to create a genuinely neutral platform for whistle-blowers while avoiding the trap of becoming “political lobbyists or pop stars” like Assange. Unlike WikiLeaks, OpenLeaks is not a publishing platform: It allows whistle-blowers to deposit material anonymously in an encrypted drop-box, and then to specify the recipient of the leak — a news outlet, a trade union or an NGO — and how long the recipient should have exclusive access. By offering a series of digital mailboxes for each of its media and other partners, OpenLeaks doesn’t have to choose between large and small leaks, and it allows sources to chose the publishing platforms they think will treat the material most responsibly. By separating the receipt of documents from their publication, OpenLeaks solves the problem of centralization that allowed Assange to accumulate too much power and to exert political influence that was more focused on his personal aggrandizement than on the public interest.

Domscheit-Berg ends with a series of questions for Assange, pressing him on WikiLeaks’s financial situation (Does Assange profit from its media deals?) and current associates, who include a father and son with a record of public anti-Semitism. Ever the idealist, he ends his book expressing the hope that OpenLeaks will be seen as the kind of “sober, neutral infrastructure” that Assange failed to deliver. For citizens around the globe who are attracted to WikiLeaks’s promise of transparency but distressed by the illiberal excesses and reckless behavior of its founder, Domscheit-Berg provides an invaluable vision of a genuinely neutral technology for whistle-blowers. And he reminds us of the danger of concentrating power in the hands of one man, whose secretive organization became the mirror image of the powerful institutions he sought to expose.

Jeffrey Rosen is a law professor at George Washington University, the legal affairs editor of the New Republic, and a nonresident senior fellow at Brookings.