The document discusses linear and non-linear data structures. It defines a data structure as a way of organizing data to be used effectively. Linear data structures like arrays, stacks, queues, and linked lists arrange data sequentially, allowing single traversal. Non-linear structures like trees and graphs arrange data hierarchically, requiring multiple traversals. Linear structures are easier to implement but use memory inefficiently, while non-linear structures use memory efficiently but are harder to implement. Examples and properties of various linear and non-linear data structures are provided.