@PauloCereda I first saw the TeXbook lying beside a brand new Macintosh Plus back in 1985 and was instantly amazed by it. But there was no TeX for the Mac at the time. It arrived some months later: it was called MacTeX (a defunct project) and I produced the first paper in TeX! My supervisor stunned at the result: he was used to typewritten papers with symbols drawn by hand.
My first "real" work with the innards of TeX was preparing a "PlainIt" format for getting correct hyphenation for Italian. Before TeX3 only one language was possible.
Then it came OzTeX, with Computer Modern fonts (MacTeX used system fonts except for math and the result was actually not that good).
The first book I prepared were the lecture notes for a course in Linear Algebra; the two teachers had written them in Word. I used AMSTeX and had to define all cross-reference macros.
The manual for AMSTeX had been written by M. Spivak and was a delight to read: The Joy of TeX. The title is a joke based on the famous book "The joy of sex" and the book followed the same pattern: the chapter titles are almost the same.
Until the nineties LaTeX was out of the question for mathematicians: it simply lacked what was needed. But when AMSTeX was ported to LaTeX as AMSLaTeX (by Schöpf and Mittelbach), a new world opened.
I was appointed professor in 1992 and went to Catania, in Sicily. There I had the opportunity of studying better TeX. I still used AMSTeX, but soon I translated my lecture notes in AMSLaTeX, which wasn't so difficult. Then two colleagues asked me to help them with a "Conference Proceedings" volume.
It was a very big work: more than 20 research papers in Mathematical Physics (which I didn't understand) full of complicated alignments and big matrices. Some of them were written in Plain TeX, some in LaTeX, others in Word or in ChiWriter.
Does anybody know ChiWriter? :)
It was an MS-DOS program which produced sort of typewritten documents, but was able to insert symbols.
Some months of work, but in the end I was quite proud of the result: the book had a uniform appearance, and many pagination problems had been solved.
Seen today, I see many weaknesses; maybe now I'd do some things differently.
"Modern Group Analysis: Advanced Analytical and Computational Methods in Mathematical Physics", Proceedings of the International Workshop Acireale, Catania, Italy, October 27-31, 1992; N.H. Ibragimov, M. Torrisi and A. Valenti (eds.); Kluwer Academic Publishers, 1993
Actually the papers were 41. Somebody may check their university library for it.
Sorry, but dinner's ready. :) Back here in an hour or so.