User blog comment:MermaidatHeart/How it All Began. :D/@comment-4722696-20140602222040/@comment-8151812-20140603223227

A maze runner is somebody who tries to solve the Maze, but nobody's been able to figure it out yet. There's a very few amount of runners, and they spend all day in the maze. (Nobody wants to be stuck in the maze when the sun sets. ;))

As for the leaders and co-leaders, they're like the ones in charge! They don't really have that big of a job in the Glade, except for showing the greenines around and keeping things in order. :)

I think you'll get it if you read the book. ;)