In his Foreword to the 1958 reissue of his Degrees of Knowledge (orig 1932) Jacques Maritain wrote the following tribute to Gerald Phelan:

I am happy to extend my very special gratitude to the captain of the [translation] team, Dr. Gerald B. Phelan, who directed, supervised and revised the whole work. I deeply appreciate the great testimony he bore to our long and affectionate collaboration in spending thus so much of his time for my book’s sake, and allowing this new translation to profit not only by his mastery of the subject matter but also by his mastery of the French and English languages. I avail myself of the present opportunity to pay my tribute of loving gratitude to this incomparable friend. When I first came to this continent, some twenty-five years ago, it was because, in his capacity as President of the Institute of Mediaeval Studies, he had invited me to give a series of lectures. I was immediately captivated by the eminent qualities of his mind and the charity of his heart and by the way in which were united in him love for truth and philosophical wisdom, in all their objectivity, and evangelic love of one’s neighbour. This was the beginning of an intellectual fellowship which has been especially dear to me. And from that time on, I cannot count the proofs of steadfast support and generous cooperation I have received from him. The last, and not the least, is the present translation.