"There have been a variety of Mario role-playing games released in the Mario series' history. The first was Square Soft's Super Mario RPG: Legend of the Seven Stars. This game has never received a direct sequel, although as it was the first game to put Mario into an RPG environment. The Paper Mario and Mario & Luigi games are usually considered spiritual sequels. The next game was Paper Mario, which was later followed by Paper Mario: The Thousand-Year Door and Super Paper Mario, the latter being a platform game with role-playing elements - unlike earlier Mario role-playing games which were role-playing games with platform gameplay. Another spiritual sequel was the handheld game Mario & Luigi: Superstar Saga, which had a sequel called Mario & Luigi: Partners in Time, and a third installment called Mario & Luigi: Bowser's Inside Story.
This Series was created to hold all the different Mario and Luigi games."
Source: Wikipedia, "Mario_role-playing_games", available under the CC-BY-SA License.