- Divide the list of elements into two lists, of half the size of the original list
- Apply the algorithm to each of the two lists
- Merge the two sorted lists together.
This is the same as with quicksort, developed in 1960. The difference is that with merge sort, dividing the lists is trivial, and merging them together isn't. With quicksort, dividing the lists is more complex, but the merging step is trivial. Also note that merge sort is a stable sorting algorithm, while quicksort isn't.