+The **complex derivative** extends the familiar idea of a derivative to [Complex Functions](/wiki/complex_function). For a function to be differentiable at a [Complex Number](/wiki/complex_number), its limit must exist uniquely from any direction in the complex plane. This strong condition defines a profound class of functions with remarkable properties.
+## See also
+- [Complex Analysis](/wiki/complex_analysis)
+- [Holomorphic Function](/wiki/holomorphic_function)
+- [Cauchy-Riemann Equations](/wiki/cauchy-riemann_equations)