This document discusses data structures and algorithms related to queues. It defines queues as first-in first-out (FIFO) linear lists and describes common queue operations like offer(), poll(), peek(), and isEmpty(). Implementations of queues using linked lists and circular arrays are presented. Applications of queues include accessing shared resources and serving as components of other data structures. The document concludes by explaining the eight queens puzzle and presenting an algorithm to solve it using backtracking.