Recursion is a programming technique where a function calls itself to solve a problem. It’s particularly useful for problems that can be divided into smaller, similar subproblems, such as traversing trees, computing factorials, or solving puzzles like the Tower of Hanoi. In recursion, the function keeps calling itself with modified inputs until a base condition is met, at which point the recursion stops, and the results are combined to produce the final solution. In TypeScript, recursion can be implemented in the same way as in other languages by having a function call itself within its body. For example, to calculate the factorial of a number, a recursive function would call itself with the number decremented by 1, continuing until it reaches 1. Recursion is often more intuitive than iterative solutions for problems like tree traversal (in-order, pre-order, post-order), depth-first search (DFS) in graphs, and backtracking algorithms. However, recursion can be less efficient than iteration in some cases because it requires additional memory to maintain the call stack. Tail recursion is an optimization technique that some compilers can use to reduce the overhead of recursive calls. Understanding recursion is vital for tackling a wide range of algorithmic problems, especially those involving divide-and-conquer strategies.