A SUPREMELY IMPORTANT BOOK—which until today I considered flawless—contains a major typo in the Introit for the Feast of the Transfiguration. Here is the Editio Vaticana (1908) which remains the Church’s official chant book, even in the Ordinary Form:

Can you spot which edition has a major error?
The 1953 Schwann edition has:

Fr. Weinmann’s 1909 version of the Editio Vaticana has:

My favorite book—“Mass & Vespers” (1957) by Solesmes—has:

The 1961 Solesmes Graduale Romanum has:

The Liber Usualis has:

If you need help, visit St. René Goupil and download the Introit for the Transfiguration.