Barcodes provide a very simple, reliable, machine-readable way to read numbers or addresses into your computer so that information can be looked up online or in a database. There are a number of different standards for barcodes, and the most-commonly used ones are quite easy to use and create with simple free software applications, whether you want to incorporate them directly in your cover art, or make stick-on labels for marking packages. Here, I’ll walk you throught the basics of three popular types of barcodes: UPC, EAN (including ISBN), and QR codes.

Producing the barcode itself is trivial in Inkscape — the leading Free/Open Source Software vector drawing application — ever since the extension became part of the standard distribution, with version 0.46. The current version supports several kinds of barcodes, including the UPC and EAN types.