AMS-TeX

AMS-TeX is a macro package that Michael Spivak wrote on top of plain TeX for the American Mathematical Society (AMS). It was its own format, built for high-quality mathematical typesetting — and its math machinery was later ported into LaTeX, becoming the ancestor of the amsmath we use today. The original AMS-TeX is now almost never invoked directly.

What AMS-TeX is

AMS-TeX is a format (macro package) layered on Knuth’s plain TeX (the basic set of macros). It is a separate lineage from LaTeX — at the time it was another way of “using TeX,” parallel to Lamport’s LaTeX. Michael Spivak built it for the AMS in the early 1980s, and the AMS used it for journal and book production from 1983 to 1985. Its usage is documented in the manual The Joy of TeX.

Its hallmark was the quality of its mathematics. Multiline aligned equations (\align), commutative diagrams (the machinery behind amscd), matrices via \matrix, and delicate handling of subscripts and nested fractions — constructs that were laborious in bare plain TeX — could now be set beautifully with far less burden on the author. AMS-TeX played a decisive part in establishing TeX as the standard for mathematics publishing.

Because it is its own format, you processed it with a dedicated command, amstex, and the markup differs from LaTeX. Instead of LaTeX’s \documentclass … \begin{document} … \end{document}, the body was wrapped in \document … \enddocument, the title set with \title, and headings with \head and similar commands of its own.

For symbols and alphabets, the AMSFonts collection that the AMS assembled sits underneath. The blackletter/fraktur \frak and the blackboard-bold (hollow bold) \Bbb — alphabets familiar to mathematicians — come from here, and were later carried over verbatim into the LaTeX world.

Relationship to amsmath / AMS-LaTeX

This is the crucial point. As LaTeX became the de facto standard, AMS-TeX’s excellent math features were ported into the LaTeX world. The result is AMS-LaTeX: concretely, the amsmath, amssymb, amsthm, and amscd packages, together with the AMS document classes amsart (articles), amsbook (books), and amsproc (proceedings).

In other words, a modern author gets AMS-TeX’s quality simply by writing \usepackage{amsmath} in LaTeX. The math environments such as align, the theorem environment (amsthm), and commutative diagrams (amscd) all descend from this line. The same holds for the symbol fonts: loading amssymb pulls in amsfonts internally, giving you \mathbb (blackboard bold, from the msbm font) and \mathfrak (fraktur, from the eufm font). msam and msbm are the AMS’s extra symbol fonts.

The contrast below makes it concrete. On the left is an aligned display in the AMS-TeX style; on the right is its modern LaTeX (amsmath) equivalent. The markup differs, but the goal is the same — a multiline display aligned on the equals signs.

% AMS-TeX (legacy: processed with the amstex format)
\align
  (a+b)^2 &= a^2 + 2ab + b^2 \\
  (a-b)^2 &= a^2 - 2ab + b^2
\endalign

% Modern LaTeX equivalent
\usepackage{amsmath}
% ...
\begin{align}
  (a+b)^2 &= a^2 + 2ab + b^2 \\
  (a-b)^2 &= a^2 - 2ab + b^2
\end{align}

The AMS still distributes and recommends these packages and classes (AMS-LaTeX) for authors. The standalone AMS-TeX format, by contrast, is legacy: it remains on CTAN as a historical record, but the AMS itself explicitly states that it does not recommend creating new documents with AMS-TeX.

In short, if you write math in LaTeX today, you are using AMS-TeX’s legacy through amsmath, and you do not need to invoke the original AMS-TeX format. TeX Live 2026 still ships amstex, but the CTAN distribution has been frozen since the v2.01 "final archival" release in August 2021 and is kept mainly for processing old manuscripts. The LaTeX-side amsmath, by contrast, is jointly maintained by the LaTeX3 Project and the AMS and is still actively updated (v2.17z, July 2025).

How to write new math documents today

The history matters because it guides today’s choice. For a new report, lecture note, or paper, do not start the amstex command. Start a LaTeX document and load the AMS-LaTeX packages you need: amsmath for aligned displays, amssymb for extra symbols such as blackboard bold, and amsthm for theorem, lemma, and proof structures.

\documentclass{article}
\usepackage{amsmath,amssymb,amsthm}

\newtheorem{theorem}{Theorem}

\begin{document}
\begin{theorem}
For real numbers $a$ and $b$,
\begin{align}
  (a+b)^2 &= a^2 + 2ab + b^2.
\end{align}
\end{theorem}
\end{document}

For an AMS journal or book you may additionally use classes such as amsart or amsbook. The document model is still LaTeX: begin with \documentclass, then build title, author, abstract, and theorem structures in LaTeX’s style. The lesson from AMS-TeX is not to memorize legacy commands; it is to mark mathematical structure by meaning.

• Use \begin{document}, not the AMS-TeX \document, as the body entry point.
• Use \section and friends for headings rather than \head.
• Do not hand-style theorem statements in the old \proclaim spirit; create numbered structures with \newtheorem.
• Use \mathbb from amssymb instead of the legacy \Bbb.

When you inherit an AMS-TeX manuscript

You may inherit an AMS-TeX manuscript from old lecture notes, a lab archive, or a publisher’s source bundle, usually recognizable by \document and \enddocument. The first task is not modernization; it is to preserve a reproducible baseline PDF. Keep the source, figures, fonts, and log together, process it first with the amstex still shipped in TeX Live, and only then migrate chapter by chapter to LaTeX + amsmath against that baseline.

• Preserve first: try amstex oldfile.tex before changing the source.
• Write new material in LaTeX: once you revise, move to \documentclass plus amsmath.
• Do not bulk-convert blindly: migrate \align to the align environment and \Bbb to \mathbb in small steps.
• Compare the PDFs: equation numbers, line breaks, and theorem counters are the parts most likely to shift.