The January 1975 issue of Popular Electronics carried a cover photograph of the MITS Altair 8800 and the headline announcing the “World’s First Minicomputer Kit to Rival Commercial Models.” Inside, a construction article by H. Edward Roberts and William Yates, titled “ALTAIR 8800: The most powerful minicomputer project ever presented — can be built for under $400,” described how a reader could build a genuinely programmable computer for a price within reach of a hobbyist. The issue is preserved in full at the World Radio History Poptronics archive.
The article ran as a typical Popular Electronics build feature: photographs of the assembled machine, block diagrams, a description of the Intel 8080-based architecture, a parts list, and an order coupon for MITS in Albuquerque. What set it apart was the subject. Earlier kit projects had been calculators, test gear, and toy-scale digital devices; this one was a stored-program computer with 256 bytes of memory expandable through an open bus, presented as something an ordinary enthusiast could own and program.
The effect on readers was immediate and far larger than either the magazine or MITS expected. Roberts had hoped to sell a few hundred units to keep his struggling company alive; instead the issue triggered thousands of orders and inquiries, and MITS scrambled to fill them. The article turned a theoretical possibility into a shipping product that hobbyists could buy, and it gave the nascent personal-computer hobby a concrete rallying point.
The cover story also set in motion the events that defined the era. It inspired Bill Gates and Paul Allen to write a BASIC interpreter for the Altair, leading to the founding of Microsoft. It helped catalyze the formation of the Homebrew Computer Club in Menlo Park, where members compared notes on building and extending machines like the Altair. And it established the Intel 8080 and the Altair’s open bus, later standardized as the S-100 bus, as a de facto platform that other companies built compatible hardware and software for.
Because of this chain of consequences, the January 1975 Popular Electronics issue is routinely cited as the spark of the personal-computer revolution. It is a rare instance in which a single magazine article can be pointed to as the moment a hobby, an industry, and an entire mode of computing began.