MiKTeX (pronounced mick-tech) is an up-to-date implementation of TeX/LaTeX and related programs.
TeX is a typesetting system written by Donald Ervin Knuth who says that it is intended for the creation of beautiful books – and especially for books that contain a lot of mathematics.
It is very easy to install MiKTeX on Windows. The MiKTeX Setup Wizard guides you through the installation process. You don’t have to be a computer expert. On a Mac, you can use the Drag’n’Drop installer to install MiKTeX.
A complete set of additions (programs, styles, fonts, …) are available to help you typeset your documents.