Dragon Ball Z (ドラゴンボールゼット Doragon Bōru Zetto?, commonly abbreviated as DBZ) is the long-running anime sequel to the Dragon Ball TV series, adapted from the final twenty-six volumes of the Dragon Ball manga written by Akira Toriyama. The manga portion of the series debuted in Weekly Shōnen Jump in October 24, 1988 and lasted until 1995; the anime adaptation premiered in Japan on Fuji Television on April 26, 1989, taking over its predecessor's time slot, and ran until its end on January 31, 1996, lasting 291 episodes in Japan, and 276 episodes in the United States originally, although all 291 episodes were later broadcast when content from the first 67 episodes was restored.
Dragon Ball Z uses four pieces of theme music in the Japanese version. From episodes 1-199, the opening theme is "Cha-La Head-Cha-La" by Hironobu Kageyama, and the closing theme is "Detekoi Tobikiri Zenkai Pawā!" by MANNA. From episodes 200-291, the opening and closing themes are "We Gotta Power" and "Boku-Tachi wa Tenshi Datta," both by Hironobu Kagayama.
A note on the "Season" nomenclature:
The "seasons" that comprise the following list correspond to the remastered box sets released by Funimation from 2007 to 2009. However, these "seasons" only correspond to story arcs (which are themselves split at debatable points), and not to the pattern in which the show actually aired in either Japan or the United States.