Development of the Animatrix project began when the film series' writers and directors, the Wachowski brothers, were in Japan promoting the first Matrix film.
The Animatrix was conceived and overseen by the Wachowski brothers but they only wrote four of the segments themselves and did not direct any of them; most of the project was created by notable figures from the world of Japanese animation.
Animatrix is a combination of various anime directors coming together to create 9 short stories for the Matrix.
The Animatrix is composed of 9 short animated films, all of which are Matrix-themed, but are completely unrelated to each other, with the exception of "The Second Renaissance, Parts 1 and 2." As such, each deserves a separate review.
Four of the Animatrix stories are penned by the Wachowski Brothers, with the remaining five written by the anime directors themselves.