Few companies have a beginning as auspicious as MXR. The effects pedal pioneer was founded in 1973 by the late Keith Barr, Michael Laiacona, and Terry Sherwood. If those names don't sound familiar, they should. In addition to MXR, these gentlemen also either founded or co-founded Alesis, ART, and Whirlwind - not a bad pedigree.
The early MXR pedals were handmade in the founders' basement and are considered highly collectible today. These so-called "Script" pedals (due to the script logo) used high quality carbon film resisters and are renowned for their warm, rich tone. Some of the most popular of the early MXR pedals are the Phase 90 (heard extensively on the first two Van Halen albums), the Dyna Comp (a favorite of studio guitarists), and the Distortion + (preferred by Randy Rhoads). MXR also produced a well-regarded line of rack effects, used by everyone from David Gilmour to Mike Rutherford.
Currently, Jim Dunlop has the rights to the MXR brand and has reissued several of the classic MXR effects, including the ones mentioned above. In addition to the original line, Dunlop/MXR has several signature pedals produced with MXR devotees Eddie Van Halen and Zakk Wylde.