LyX is a GUI frontend to the LaTeX typesetting software which allows you to produce professional-quality typesetting without the need to learn the TeX language, or to know the rules of professional quality typesetting. Please note that, when properly typeset, the inner margins should each be about half the size of the outer margins so that when the book is opened out to lie flat, the margin whitespace between text blocks should appear equal.

LyX documents are text files and can therefore also be edited manually with standard editors such as vi(m), (x)emacs, etc. They are compact (about 3 kilobytes per printed page). Typically the PDF version of a LyX file will be twice that size. LyX files are converted into the TeX language (also text) and then compiled by the program: latex into a device independent .dvi format (binary) which various converters can render into .ps (Postscript), .pdf (Portable Document Format), .html (HyperText Markup Language), .odt (Open Document Format), plain text using common opensource utility programs, and several other formats which require 3rd party software.