Who is Rebecca Barren?

Rebecca from the first reality died before the events of the novel, and we only learn a few details about her from Tom. She fell into the role of a housewife early on in her marriage with Victor, giving up much of her own identity in order to make his life as easy as possible so he could focus on science. This lead to a deep, isolating depression which she hid from the world, only sharing with Tom. She was unique in her love for books, a medium almost totally discarded, replaced with high-tech narrative simulators.