Like TeX, LaTeX started as a writing tool for mathematicians and computer scientists, but
from early in its development it has also been taken up by scholars who needed to write documents that
include complex math expressions or non-Latin scripts, such as Arabic, Sanskrit and Chinese.
LaTeX is intended to provide a high-level language that accesses the power of TeX in an easier way for
writers. In short, TeX handles the layout side, while LaTeX handles the content side for document
processing. LaTeX comprises a collection of TeX macros and a program to process LaTeX documents. Because
the plain TeX formatting commands are elementary, it provides authors with ready-made commands for
formatting and layout requirements such as chapter headings, footnotes, cross-references and
bibliographies.
TeX vs. LaTeX
TeX
TeX is a typesetting system (or "formatting system") designed and mostly written by Donald Knuth and released in 1978. Together with the Metafont language for font description and the Computer Modern family of typefaces, TeX was designed with two main goals in mind: to allow anybody to produce high-quality books using minimal effort, and to provide a system that would give exactly the same results on all computers, at any point in time. TeX is a free software. TeX is a popular means of Typesetting Complex Mathematical formulae. It has been noted as one of the most sophisticated digital typographical systems. TeX is popular in academia, especially in mathematics, computer science, economics, engineering, linguistics, physics, statistics, and quantitative psychology. It is also used for many other typesetting tasks, especially in the form of LaTeX, ConTeXt, and other macro packages.
QUOTE [Wikipedia]
LaTeX confronted with TeX