The these are part of the Voice of the Vicar of Christ Series by Rev. Gerald C. Treacy, S.J. with all first published before 1950 and published as pamphlets by The Paulist Press of New York.
Praying With Christ (On the Encyclical Mediator Dei from Pope Pius XII)
Christian State or Pagan Chaos (On the Encyclical Immortals Dei from Pope Leo XIII)
Liberty-Man’s Greatest Gift (Human Liberty from Pope Leo XIII)
Heaven’s Beginning (On the Encyclical Mystici Corporis Christi from Pope Pius XII)
Labor’s Charter of Liberty (On the Encyclical Rerum Novarum from Pope Leo XIII)
God and Liberty against Satan and Slavery (On the Encyclical Divini Redemptoris from Pope Pius XI)
Rebuilding Society’s Social Order (On the Encyclical Quadragesimo Anno from Pope Pius XI)
Love Undying (On the Encyclical Casti Connubii from Pope Pius XI)
Education: True or False (On the Encyclical Divini Illius Magistri from Pius XI)
I also found out that Father Treacy also published a book called Atheistic Communism: Encyclical Letter of His Holiness Pope Pius XI which I do not know the publisher for but found it on the Internet and plan to order it.