The Laurent series is a power series with a non-negative power series and a meromorphic function as coefficients. It's like the math equivalent of a trusty sidekick, always there to lend a helping hand when you're dealing with complex functions.
But don't just take our word for it! Check out the convergence theorem for yourself:
Laurent series = meromorphic function * (1 / (z - z0))
See? Easy peasy. Now, go forth and conquer the world of complex analysis!
See the Proof