The package uses a text font (usually the document's text font) for the letters of the Latin alphabet needed when typesetting mathematics. (Optionally, other characters in the font may also be used). This facility makes possible (for a document with simple mathematics) a far wider choice of text font, with little worry that no specially designed accompanying maths fonts are available. The package also offers a simple mechanism for using many different choices of (text hence, now, maths) font in the same document. Of course, using one font for two purposes helps produce smaller PDF files.