The Early History of Smalltalk

A detailed first-person account traces how interactive time-sharing, graphical displays, and a desire for personal computing in the 1960s and 1970s led to the invention of Smalltalk and the object-oriented paradigm. It argues that exponential growth in computing demanded a qualitative shift: machines for millions of users had to be learning environments, reduce complexity, and use a unified, biologically inspired model of computation. Smalltalk’s core idea is that every entity is an object combining state and behavior, interacting solely by message passing; this recursion on the notion of computer postpones low-level representation and lets systems be composed from self-contained, communicating units. Philosophically grounded and deliberately extreme, the design treats objects as idealized “Ideas” and positions object-oriented design as a new crystallized style of programming rather than an agglutination of features.

The narrative follows technical and organizational evolution from early influences like Sketchpad, Simula, and LISP through prototypes at Xerox PARC (Smalltalk-71/72), the Interim Dynabook concepts, and the maturation to Smalltalk-76 and the release-quality Smalltalk-80. It highlights concrete contributions - overlapping windows, bitmap screens, icons, bytecodes, the Notetaker, ThingLab, and the later addition of inheritance - and credits key implementers who turned the vision into working systems. The account concludes that Smalltalk exemplified a Kuhnian paradigm shift, enabling both powerful professional modeling of dynamic systems and approachable environments for learners and end users.