Written By: Gehn, re-written by Catherine
Appears In: Riven, Myst IV: Revelation (mentioned)
Once on Tay, Catherine located a special crystal she had written into the Age to help clear the image on the Linking Panel and bring the faulty Books back to life without the need for Gehn's special domes to power them. The crystal which Catherine wrote into Tay was based on an earlier experiment by Atrus, which he conducted on the Rime Age, involving seeing through an unwritten Book to a specific Age. Catherine apparently made use of this experiment for her own purposes to "focus" the Books which linked to and from Tay.
Tay was eventually used as an evacuation Age for all of the Rivenese once Catherine was freed and Gehn captured. She evidently stayed in contact with her people even after that point, as she mentions in a journal in Myst IV: Revelation that she would visit Tay to take her mind off the difficulties she and Atrus were having over whether to re-establish contact with and possibly free their sons, Sirrus and Achenar. She also seemed to be in the habit of bringing Yeesha there to visit as well, as she does so following the unfortunate events that transpired during Revelation.