RAFO is the common acronym used for saying Read and Find Out. It is used with the implication that the particular question or plot-line for what one wants the answer to, will be revealed in the next, or in a future, book. It is most commonly used for a literary series. The equivalent for the TV series series is WAFO (Watch and Find Out).
—Robert Jordan, Source:Scifi.com chat, 1 November 1998