  To mark the half-century anniversary of this newly-born field of Cataclysmic
Variables, a special emphasis is made in this review, on the Doppler Effect as
a tool in astrophysics. The Doppler Effect was in fact, discovered almost 170
years ago, and has been since, one of the most important tools which helped to
develop modern astrophysics. We describe and discuss here, its use in
Cataclysmic Variables which, combined with another important tool, the
tomography, first devised for medical purposes 70 years ago, helped to devise
the astronomical Doppler Tomography, developed only two decades ago. A
discussion is made since the first trailed spectra provided a one dimensional
analysis of these binaries; on the establishment of a 2D velocity profiling of
the accretion discs; and unto modern techniques, which include Roche
Tomography, time modulation and 3D imaging.
