The discovery of Episodic Tremor and Slip (ETS) was only about 13 years ago, first in Japan and then in Cascadia. Seismologists at the University of Washington have been deeply involved with it’s study using both regional seismic network data as well as directed special studies using seismic arrays. This talk will summarize what ETS is, how we monitor it, some of its strange properties and include speculation as to its cause and possible uses for understanding the earthquake cycle.