Modern Vector Network Analyzers (VNAs) have flexible hardware and software with much higher performance than VNAs of even a few years ago. Modern VNAs address a wide range of applications, and current versions can address almost every type of RF measurement. This talk will detail the evolution of Network Analyzers from their early implementation as fast power meters to the advanced component test systems they are today. We will take a look at the advanced technology inside that allows VNA to achieve supreme accuracy not only in S-parameter measurements, but in nearly all areas of characterization including Noise Figure, TOI, Modulation/Distortion, Spectrum Analysis and Active Device characterization.