The following resources are strongly recommended:
The Priest is Not His Own, by Fulton Sheen (Ignatius Press, 2004)
Profound and deeply spiritual look at the meaning of the priesthood and relationship of the priest with Christ as an "alter Christus". Available as a free audiobook here on Formed!
Magnificat Year for Priests Companion (Magnificat, 2009)
Prayers, devotions, meditations, essays celebrating priesthood. Special Novena in honor of Priesthood, each day highlighting a different dimension of the priestly vocation.
The following resources might also prove helpful:
Conformed to Christ Crucified: Meditations on Priestly Life and Ministry, by Joseph Carola, S.J., 2 volumes (Gregorian Biblical Bookshop, 2010)
These meditations call the priest to be one with Christ Crucified for God’s glory and the salvation of souls.
Gift and Mystery: On the Fiftieth Anniversary of My Priestly Ordination, by St. John Paul II (Image, 1999)
Reflections on his own priestly vocation by a modern saint.
He Leadeth Me, by Fr. Walter Ciszek, S.J., with Daniel Flaherty (Image, 2014)
American Jesuit priest captured by Russian army during WWI. Spent 22 agonizing years in Soviet prisons and labor camps of Siberia. Extraordinary testimony of faith and perseverance in priesthood.
Letters to a Brother Priest, by Fr Vincent Martin Lucia and Msgr Josefino Ramirez (M.B.S., 2011)
Letters to a new priest, encouraging love of the Eucharistic Lord.
Praying for Priests: A Mission for the New Evangelization, by Kathleen Beckman (Sophia Institute Press, 2014)
The Catholic Priest – Image of Christ, by Steen Heidemann (Ignatius Press, 2009)
Coffee table size book – jam-packed with stunning artistic images through 15 centuries of art – complemented with corresponding short texts about the priesthood.
The Scarlet and the Black (Film, 1983)
True story of Monsignor Hugh O’Flaherty, hero of the Vatican Underground. Based on the book The Scarlet Pimpernel of the Vatican by J.P. Gallagher. Starring Gregory Peck and Christopher Plummer.
Why Priests? by Paul Josef Cardinal Cordes (Scepter Publishers, 2010)
Reflections on the priesthood that draw on the thought of Pope Benedict XVI.