Donald Knuth created TeX as a programming language and typesetting system for producing high-quality mathematical and scientific documents.
Knuth began developing TeX in the late 1970s after becoming dissatisfied with the quality of typography in the typeset editions of his books. The first publicly released version appeared in 1978, and the system was designed to give authors precise control over page layout, fonts, mathematical notation, and document structure.
TeX is often confused with LaTeX. TeX is the underlying typesetting system and language, while LaTeX is a higher-level document-preparation system built on top of TeX and created by Leslie Lamport. TeX is also different from METAFONT, another Knuth-created system used to design fonts.
The system became especially influential in mathematics, computer science, physics, and other fields where complex formulas are common. Its name is usually written as TeX, with the letters traditionally styled to suggest the Greek letters tau, epsilon, and chi.