For philatelists focusing on French, European, or colonial postage stamps, the is not merely a reference—it is the industry standard. Founded in 1895 in Amiens, France, this venerable institution has spent over a century cataloging the world's stamps, becoming an essential tool for collectors seeking accurate identification, detailed history, and updated market valuations.

The Yvert et Tellier catalogue is a well-known and respected reference for philatelists (stamp collectors). It provides detailed information on postage stamps from around the world, including their values, issuing dates, and other relevant data. This catalogue is published in various formats, including print and digital.

Unlike a web app that disappears when the subscription ends, a Yvert PDF is a zombie. It never dies. You can keep the 2014 PDF on a hard drive forever. This creates a fascinating secondary market: collectors comparing the trajectory of prices over a decade by cross-referencing old PDFs, something nearly impossible with paper (unless you have a very large library).