That reminds me about dictating my earliest Radio Shack books into a portable tape recorder while riding my bike 20 miles every afternoon. My wife Minnie typed those books from the recording. Dictation wasn't feasible with the hand-lettered books, which had to be carefully designed in advance to fit everything on one or two pages per topic.
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The first few pages were prepared with a Selectric typewriter. I then inserted a signature to ease the reader into the hand lettered concept Dave wanted. After several pages, the book shifted to entirely hand-lettering and illustrating. The book was written/drawn with India ink on toothed Mylar, which meant a single error required redoing an entire page. This was a very tedious project, which drew blood from the middle finger of my right hand.

I also developed PIP--Programmable Instruction Processor--for Popular Electronics magazine and "Understanding Digital Computers" (Radio Shack). PIP was a 4-bit programmable controller made from discrete TTL chips. PIP had half a dozen microinstructions. Data and programs were loaded using punched strips of paper with 4 holes for data/instructions and a middle 5th hole for the input clock. These paper strips were pulled through a slot fitted with 5 LEDs facing 5 phototransistors. The complete PIP was assembled on our kitchen table, where it occupied around 2 square feet. BTW, PIP used 3-state logic for the bus. This allowed data and instructions to use the same bus.

After co-founding MITS, the company that would later go on to produce the Altair 8800, Mims was gaining quite a reputation in hobby electronics and as a writer. With a monthly column in Popular Electronics magazine by 1975 and a couple of volumes of hobbyist books written for Howard Sams and Company, Radio Shack’s technical editor Dave Gunzel approached Mims about working for them. He knew of Mims’ notebook style and asked if it would be possible to develop a book using the same layouts.

Hat tip to Jac G!