Below is a list of Catholic books and online sources for when people ask, "What does the Church say about that?" So it's basically a list of the "Essential Catholic Books on Church Teaching."
Primary sources:
Secondary sources:
  • Writings of Conferences of Bishops
  • Writings of the Saints
  • Catholic spirituality classics
  • Catholic almanacs
  • Collections of Catholic prayers and devotions
  • Encyclopedias
  • Theological dictionaries
A geyser pours forth water, like the 
Church pours forth truth.

. . .The church of the living God, the pillar and bulwark of the truth.
-- 1 Tim. 3:15