Linked lists are dynamic data structures composed of nodes containing data and a reference to the next node. Implementation begins with defining a node struct/class with fields for the stored value and a pointer to the next (and previous for doubly linked lists). Insertion at the head requires allocating a new node, setting its next pointer to the current head, and updating the head reference, achieving O(1) time. Insertion at the tail either traverses the list (O(n)) or maintains a tail pointer for constant time. Deletion removes a node by re‑linking its predecessor to its successor; for doubly linked lists both previous and next pointers must be adjusted. Circular lists link the last node back to the head, and an empty circular list is identified by a NULL head. Proper memory management uses malloc/free (or new/delete) and careful handling of edge cases such as empty or single‑element lists to avoid leaks and dangling pointers.