This document discusses queues and related data structures. It defines a queue as a first-in, first-out collection where items can be inserted at the rear and deleted from the front. Algorithms for array and linked list implementations of queues are presented for insertion and deletion operations. Priority queues are described as ordered queues where the highest or lowest priority item is always at the front. Deques allow insertion and deletion from both ends and are more versatile than regular queues or stacks.