Amanda Grayson was a Human teacher from Earth born around the turn of the 23rd century. During the early 2230s, Amanda met Sarek , the Vulcan Ambassador to Earth. The two later married, and she returned to Vulcan with Sarek.
In later years, in describing his parent's relationship, Spock stated that his mother "considered herself a very fortunate Earth woman."
In 2230, Amanda gave birth to her only son, Spock.
Captain Kirk was at a loss on how to properly refer to her, calling her "Mrs. Sarek." Amanda said that her married name was usually unpronounceable by Humans, although she could do it, "after a fashion, and with many years of practice." She said to simply call her "Amanda." In the Vulcan society, she was referred to as "the Lady Amanda."
In 2286, Amanda helped her son to re-educate himself, after his death and rebirth on the Genesis Planet and fal-tor-pan rejoining. In particular, she tried to help Spock rediscover his Human side.
Years after her death, Sarek hadn't forgotten her. During his Bendii Syndrome, he regretted not having been tender to her, and having never told her how much he loved her.