Collected Origins was a rare book of prophecy written as a story.
It can be safely assumed that Collected Origins was completely about Kahlan Amnell, the Mother Confessor. This was because in Chainfire, Nathan Rahl and Annalina Aldurren found a copy and it was completely blank. It was blank because the Chainfire spell that has been set off by the Sisters of the Dark has erased the memory of Kahlan from existence. It supposedly also told the love story of Richard Rahl and Kahlan Amnell.