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 (
λ
), and the undisturbed jet diameter (
D
). These include the random breakup region for
λ/D
< 3, short wavelength Rayleigh breakup region for 3 <
λ/D
< 5.5, medium wavelength Rayleigh breakup region for 5.5 <
λ/D
< 11, and long wavelength Rayleigh breakup region for
λ/D
> 11. Except for the random region (
λ/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.