At the heart of today’s most successful and innovative companies is design. It’s a discipline that has the power to improve every aspect of our lives.

Hoefler & Frere-Jones, the preeminent digital type foundry, has broken out into civil war.

Type designer Tobias Frere-Jones claims he has been cheated out of his half of the company by his business partner, Jonathan Hoefler. In a blistering lawsuit filed today in New York City, Frere-Jones says he was duped into transferring ownership of several fonts, including the world-famous Whitney, to Hoefler & Frere-Jones (HFJ) on the understanding that he would own 50% of the company.

“In the most profound treachery and sustained exploitation of friendship, trust and confidence, Hoefler accepted all of the benefits provided by Frere-Jones while repeatedly promising Frere-Jones that he would give him the agreed equity, only to refuse to do so when finally demanded,” the suit claims. Here’s the full complaint:

Hoefler couldn’t immediately be reached for comment. Messages left at the offices of HFJ weren’t immediately returned. (See below for their statement.)

Frere-Jones joined the company that would come to be called HFJ in 1999. The suit portrays Frere-Jones as the firm’s design genius, and Hoefler as the business and marketing man. In public, the pair have generally been regarded as equals. But the contract that made it so, according to the lawsuit, was never written down and signed. Frere-Jones claims he had an oral contract with Hoefler that entitles him to half the company.

The dispute came to a head last year. ”Stop it. I’m working on it. Stop harassing me,” Hoefler allegedly wrote to Frere-Jones last summer. The suit claims, “On October 21, 2013, for the first time, Hoefler explicitly reneged on his personal agreement to transfer 50% of HTF to Frere-Jones.” (HTF refers to the Hoefler Type Foundry, the company’s original name.)

Frere-Jones’s lawyer, Fredric Newman, a senior partner at Hoguet Newman Regal & Kenney, said in a phone interview, ”The two partners tried to resolve it, but couldn’t, and so Mr. Frere-Jones had no choice but to sue to enforce his rights.”

The firm is perhaps the most important type designer of the 21st century. Its fonts have graced the branding of billion-dollar companies, and the covers of glossy magazines. Movie-trailer warning labels in the United States are set in Gotham, an HFJ typeface that was also famously used by Barack Obama’s 2008 presidential campaign.

Hoefler & Frere-Jones Gotham

HFJ’s typefaces have won admiration from designers by taking advantage of the limitless environment of digital design. Where most typefaces only had two weights and two styles in one width, HFJ became known for creating typefaces with several weights and several styles in several widths that included advanced features like alternate characters, and support for multiple alphabets.

Hoefler & Frere-Jones Whitney

Update (Jan. 17, 2:45pm ET): HFJ released a statement, set in the firm’s Mercury typeface, denying Frere-Jones’s claims and saying the company will henceforth be known as Hoefler & Co.: