At the birth of sound synthesis, in the labs of pioneers like Bob Moog and Don Buchla, all synthesizers were modular by necessity. As the components and processes behind the new devices became optimized, synths became more compact, fixed and reliable. With the introduction of the Eurorack format from Doepfer in 1995, synth lovers were able to combine the stability and portability of modern synths with the flexibility and customization of a modular method. In the past 5 years, interest in the Eurorack approach has exploded. Many engineers, enthusiasts and boutique manufacturers have been bolstering the format with a variety of modules that let anybody build a custom synth, ranging from ultra-classic to bleeding-edge experimental and anywhere in between.