Jef Raskin, the man largely credited as the founder of the Macintosh, has died Saturday at age 61.

Raskin joined Apple in January 1978 as employee No. 31, but left four years later after a well-publicized dispute with Steve Jobs. His work, however, was continued and culminated in the Macintosh personal computer, released in 1984.

In his later years, Raskin worked on The Humane Environment (THE), a system which incorporated his elements using open-source, into a Zooming User Interface (ZUI).

Raskin is also the author of The Humane Interface, a book about human interface design, in which he asserts that humans will no longer tolerate complicated interfaces to do simple tasks.