Picard iteration is a method used to solve differential equations, particularly initial value problems. It involves starting with an initial guess for the solution and then refining that guess through a series of iterations. Each iteration uses the previous guess to compute a new approximation, gradually converging to the actual solution. The process is named after the French mathematician Émile Picard, who developed this technique. Picard iteration is particularly useful because it provides a systematic way to approach complex problems, making it easier to find solutions that may not be easily obtainable through other methods.