The Apple Mouse began as one of the first commercial mice available to consumers.

It was there they discovered the mouse, invented by Douglas Engelbart while he was working at SRI International (SRI); the mouse had subsequently been incorporated into the graphical user interface (GUI) used on the Xerox Alto.

During an interview, Engelbart said "SRI patented the mouse, but they really had no idea of its value.

Some years later it was learned that they had licensed it to Apple for something like $40,000." One of the biggest problems was that the three button Xerox mouse cost over US$400 to build, which was not practical for a consumer-based personal computer.

Apple commissioned Hovey-Kelley Design (which later became IDEO) to assist them with the mouse design, which not only had to be redesigned to cost US$25 instead of US$400, but also needed to be tested with real consumers outside a laboratory setting to learn how people were willing to use it.

Not much later, it was redesigned to be slightly angular along the top; this mouse is commonly called the "trapezoid mouse" for its slight trapezoid shape on the bottom.

In 1993 Apple redesigned the package to be egg-shaped, which was widely copied throughout the industry.

Nevertheless, it was still a tool available only in corporate gray or (rarely) black.

Hundreds of prototypes later, Apple settled on a single button mouse, roughly the size of a deck of cards.

With the design complete, the operating system was adapted to interface with the single button design using keystrokes in combination with button clicks to recreate some of the features desired from the original Xerox three-button design.