It's called professional typesetting. The manuscript sent to BSTJ would have been typed, probably double-spaced, and I assume with hand-drawn equations. Once ed

It's called professional typesetting. The manuscript sent to BSTJ would have been typed, probably double-spaced, and I assume with hand-drawn equations. Once editing was finished, it would go to the typesetter. Answers on this Stackexchange thread go into some detail: https://tex.stackexchange.com/questions/244082/typesetting-before-tex-and-computers https://tex.stackexchange.com/questions/244082/typesetting-b... On page 290 of a linked source you can see an example of typed/handwritten copy that the typesetter (a person) would have been working from: https://gwern.net/doc/design/typography/2003-matrix-typeandtypography.pdf https://gwern.net/doc/design/typography/2003-matrix-typeandt...