energy was transformed into an electromagnetic outflow. Two distinct types of non-monotonic behavior were established: “timing noise” characterized by a stochastic wandering in pulse phase and/or frequency which appeared to afflict most pulsars (Helfand, Taylor, and Backus 1980; Cordes and Helfand 1980; Cordes and Downs 1985; D’Amico et al. 1998), and “glitches”, an apparently instantaneous increase in the pulse frequency (a spin-up) accompanied by a simultaneous change in the spin-down rate; these rare events were found to be most prevalent in young objects (Reichly and Downs 1971; Lyne 1996 and references therein). Thirty years after the first glitch in the Vela pulsar was recorded, a total of 65 events have been seen in 27 different pulsars (Lyne 1996; Wang et al. 2000).

Glitches are a sudden fractional increases in the pulsar spin frequency with $\delta\nu / \nu \approx 10^{-9} \ {\rm to} \ 6
\times 10^{-6}$. No pulsar with a characteristic age of $>10^6$ yr has been observed to glitch more than once, but some young objects experience these events roughly annually. The best studied and most prolific in terms of large glitches is the first object in which a glitch was seen – the Vela pulsar. A dozen events 