The novel series began in 2017 and has five volumes out so far written by Yuichiro Higashide with illustrations by NOCO.
The third season under the name Date A Live III landed as part of the winter 2019 season and we learned in September that the spinoff novel series Date A Live Fragment: Date A Bullet is in the works for an anime adaptation.
The property has seventeen volumes of the light novels released so far with Funimation bringing out the anime in North America.
Check out our review of the first season and second season of Date A Live.