While the HP computers and calculators were well documented and their design process was also frequently described in HP Journal or other HP publications, the most valuable HP publications were about their measurement instruments.

Many of the ancient service manuals for HP measurement instruments were much better for learning electronics engineering than most university manuals.

I understand, but that’s a shame.

Way back, talking 1980 or so, my father got a newsletter cum magazine of sort from HP. Marketing material to be sure, but not just raw marketing. Some corporate organ that could easily been called something like “HP Today”.

But inside was, at the time, a science fiction story about handheld computers in the future. It was a fascinating bit of “snapshot in time” that I would enjoy seeing again.

In the off-topic calculator department: hpcalc.org :)

I have an HP 48 (series of graphing calculators) overhead projector display (InVision 48) that may need refurbishment to work, but I just found the manual at hpcalc.org.[0]

0. https://literature.hpcalc.org/items/1290