An experimental investigation of the breakup of a liquid jet using high-speed motion pictures has revealed many different breakup mechanisms. The influence of disturbance amplitude and frequency on the breakup mechanism for a Weber number range of 25 to 160 is considered. The jet breakup is grouped into several distinct regions, depending on the disturbance wavelength ($\lambda $), and the undisturbed jet diameter (D). These include the random breakup region for $\lambda $/D < 3, short wavelength Rayleigh breakup region for 3 < $\lambda $/D < 5.5, medium wavelength Rayleigh breakup region for 5.5 < $\lambda $/D < 11, and long wavelength Rayleigh breakup region for $\lambda $/D > 11. Except for the random region ($\lambda $/D < 3), all the other regions show repeatable patterns of breakup. The boundaries between some of the distinct patterns are obtained for various Weber numbers and disturbance amplitudes. A new type of satellite merge is also discovered which is referred to as the reflexive merging satellite. Other features of the jet breakup, such as satellite/drop size ratio and breakup times, are also considered in detail.