Kaz: This must be the translation of his book "Le Tarot: des Imagiers du Moyen Age". A tremendous book which can open your eyes to new worlds.
If it is this book, then you've made an excellent buy. Although I cannot tell you whether the translation is good or not.
Wirth's knowledge was vast. And he shares it with humility and great respect for his readers. I hope you have his deck (although you will see that the publishers have not respected all the details that he mentions, and that is one thing that makes me MAD!!!!!!!
I don't think they bothered to read his book properly.)
(Don't forget he didn't bother about the Minors, so the Minors are an invention of the publishers - a commercial thing, I think, so that the deck is sold more.)