Very cool! The original sketchbook of the woman who designed the graphical interface icons for the first Mac computers:

 

Kare stayed on at Apple to craft the navigational elements for Mac’s GUI. Because an application for designing icons on screen hadn’t been coded yet, she went to the University Art supply store in Palo Alto and picked up a $2.50 sketchbook so she could begin playing around with forms and ideas. In the pages of this sketchbook, which hardly anyone but Kare has seen before now*, she created the casual prototypes of a new, radically user-friendly face of computing — each square of graph paper representing a pixel on the screen.

Read more at The Sketchbook of Susan Kare, the Artist Who Gave Computing a Human Face | NeuroTribes.