The “Handbook” is, of course, the Bible.
I cheered when I saw recently that the Holy Father has issued a statement urging Catholics to devote themselves to the private reading of the Scriptures. There’s long been a myth that the Church actively discourages and even prohibits such reading. What the Church refutes is private interpretation of the Scriptures — not the reading of them!
In fact, in recommending the Bible to the Faithful, Benedict referred to a very ancient practice of meditating upon the Scriptures called lectio divina. In monastic communities since ancient times, the readings of sacred works — the Scriptures usually, but also other religious writings, like the Church Fathers — are observed during mealtimes. A lector is appointed to read aloud to the community. After the reading, there is a period of silence where the reading is meditated upon… mentally digested, if you’ll pardon the obvious and bad pun.
Look here for some wonderful resources on this rich way of discovering the Scriptures.