I found the inscription above in a copy of the book, The Council, Reform and Reunion, by Hans Kung (Sheed & Ward, 1961). The book deals with the Catholic Church and ecumenical issues. The presentation signature, an unusual name, inspired a quick search for any connection to the author or the Catholic Church.
I found two prominent figures by the name of Adolph Marx. I was able to rule out this guy below pretty quickly. Harpo was not Catholic Bishop material, considering he was Jewish and didn't talk much (not at all in his movies).
The Adolph Marx who signed this book was the first Bishop of Brownsville, Texas. The photo below and following information were found in an online article by Travis Whitehead of the Brownsville Herald.
Bishop Adolph Marx, of Cologne, Germany, was appointed Brownsville's first bishop on July 6, 1965 and installed at his post Sept. 2.The article also mentions that Marx had been the Auxiliary Bishop in Corpus Christi, Texas. This information erased any doubt that this Marx was the one who signed the book because the book also contained this presentation card from Marx, which identifies him as Auxiliary Bishop of Corpus Christi (1962):
"Shortly after he was installed as bishop, he left for Rome to attend the meetings of the Second Vatican Council," said Brenda Nettles Riojas, spokesperson for the Brownsville diocese.
The Second Vatican Council took place from 1962-1965 and was attended by bishops from throughout the world, said the Rev. Robert Maher, vicar general of the diocese and pastor at St. Joseph's Church in Edinburg.
"Pope John XXIII, who convened the council, said that he saw the secularized world in many ways in a state of spiritual poverty, and he saw that the church possessed a treasure of spiritual riches bequeathed by Christ," Maher said. "So he wanted to find new ways to bring the riches of the church to people today. And so he called for an updating of the church."
Marx's attendance of such a notable event would be short-lived, however; he died of a heart attack Nov. 1.