Tool by Alan Kay, Dan Ingalls, Adele Goldberg, Learning Research Group of Xerox PARC (1972 – present)

A programming language and in-context development environment with powerful built-in tools like a class browser, object inspector, and debugger.

The message is the most fundamental language construct in Smalltalk. Even control structures are implemented as message sends. — Wikipedia

The late-bound, message-based interfaces of objects provide strong interposability properties: clients remain oblivious of the specific implementation they are talking to. In turn, this simplifies the customisation, extension or replacement of parts of a system, all of which can be rendered as interposition of a different object on the same client. — Stephen Kell, The operating system: should there be one? (2013)


  • suggesters: geoffreylitt, jryans
  • curators: jryans

Since I’ve been reading Alan Kay’s Quora answer/essays and find them very thought-provoking about the birth and philosophy behind Smalltalk, I thought it might be useful to download all of them. For ease of reading, and in case Quora collapses (as is the style for that kind of site). The site says the oldest one is “7 years ago” as of November 2023, so I assume Kay started writing in late 2016.

It comes to a 21 megabyte PDF with 431 pages.

I’m finding it helpful to start reading from the bottom up, so as to catch the whole thread in chronological order. Much like Ted Nelson, Douglas Engelbart, and JCR Licklider, Kay’s vision and philosophy is subtle and hard to pin down (and is not always what I thought it was), and I would really like to try to grasp it. I also really enjoy hearing his anecdotes about Xerox PARC and how that whole team was the direct continuation of ARPA-IPTO, going back beyond SAGE to WWII radar projects. And how IPTO was very specifically seeking to create a military-adjacent yet not entirely military-led vision - almost mystical in shape - for a “personal computing” which was centred on “intelligence augmentation”, with a strong emphasis on collaboration and education. Although it was a seach for personal interactive devices and internetworking (including the actual Internet), this IPTO vision very specifically did not include either the 1977 8-bit PC revolution or the 1989 World Wide Web. But this vision did permeate a lot of the late 1970s and early 1980s 8-bit magazines, particularly Byte and Creative Computing.

Methodology: Some of Quora is paywalled, but it seems that “author pages” aren’t. Basically I just clicked all the “more” links on (a lot of them), then did a little bit of F12 hacking to remove the top banner, then printed it to PDF.

For side by side reading, it’s probably also worth to look at: