Linked lists are a fundamental data structure in computer science, consisting of a sequence of elements, each contained in a “node.” The linked list node not only stores the value of the element but also contains a reference (or link) to the next node in the sequence. This allows for efficient insertion and deletion of elements, as these operations do not require shifting elements, unlike in an array. Linked lists can be singly linked, where each node only points to the next node, or doubly linked, where nodes contain links to both the next and the previous nodes. They are particularly useful in situations where the total number of elements is unknown upfront or the data size can change dynamically. However, one disadvantage is that accessing an element by index is more time-consuming compared to arrays, as it requires traversing from the head of the list to the desired position.