Star Trek: Rihannsu is a series of interlinked novels, written by Diane Duane and Peter Morwood, published by Pocket Books from 1984 to 2006. The series name was retroactively applied to the first novels with the release of new installments in 2000. A fifth novel was published in 2006. Rihannsu refers to the Romulan species first introduced in the Star Trek episode "Balance of Terror". However, the Romulan culture and language depicted in the novels are Duane's creations. The novels exist outside the continuity of the Star Trek films and televisions series.An omnibus published for the Science Fiction Book Club in 2000 is also titled Star Trek: Rihannsu. Source: Wikipedia (en)