What is the second book?

Paul's 'mystery, hidden from the beginning'
Secret teaching of Jesus, now made known through the cross ]]
Prophetic riddle which was sealed until after the cross
Training manual for the Christ child
How God speaks in verifiable ways
Hidden layer of the Bible
Proper sensus plenior of scripture
Proper Quadriga of Catholicism
Proper PaRDeS of Hebrew interpretation

2nd Book