Ivan Sutherland released SketchPad, which is at least a precursor to OOP, in 1963. Brilliant work!<p><a href="https://en.wikipedia.org/wiki/Sketchpad" rel="nofollow">https://en.wikipedia.org/wiki/Sketchpad</a><p><a href="https://engineeringcommunity.net/2025/05/02/ivan-sutherland/" rel="nofollow">https://engineeringcommunity.net/2025/05/02/ivan-sutherland/</a>
Outside the issue of OOP, Alan Kay has always been an icon to me, since I moved to Solana Beach CA in the early '80s soon after the establishment of Kaypro computers in that city.<p><a href="https://en.wikipedia.org/wiki/Kaypro" rel="nofollow">https://en.wikipedia.org/wiki/Kaypro</a>
Development of Smalltalk started in 1969, and its first release was in 1972 - which is well before 1976. As far as whether Kay invented objects, no, Simula was released in 1967, well before development of Smalltalk had started. But Kay was the one to popularize objects as we think of them today.
Discussed at the time (of the article):<p><i>Alan Kay Did Not Invent Objects</i> - <a href="https://news.ycombinator.com/item?id=19985776">https://news.ycombinator.com/item?id=19985776</a> - May 2019 (13 comments)
Alan Kay's "The Early History of Smalltalk" (1993) is long, and absolutely worth a read, and includes this memorable bit about Kay seeing Simula for the first time:<p>> <i>Finally, another graduate student and I unrolled the program listing 80 feet down the hall and crawled over it yelling discoveries to each other. The weirdest part was the storage allocator, which did not obey a stack discipline as was usual for Algol. A few days later, that provided the clue. What Simula was allocating were structures very much like the instances of Sketchpad. There were descriptions that acted like masters and they could create instances, each of which was an independent entity. What Sketchpad called masters and instances, Simula called activities and processes. Moreover, Simula was a procedural language for controlling Sketchpad-like objects, thus having considerably more flexibility than constraints (though at some cost in elegance) [Nygaard, 1966, Nygaard, 1983].</i><p><a href="https://worrydream.com/EarlyHistoryOfSmalltalk/" rel="nofollow">https://worrydream.com/EarlyHistoryOfSmalltalk/</a><p><a href="https://dl.acm.org/doi/10.1145/155360.155364" rel="nofollow">https://dl.acm.org/doi/10.1145/155360.155364</a>