  Over the past decade, new data from HERMES, Jefferson Lab, Fermilab, and RHIC
that connect to parton propagation and hadron formation have become available.
Semi-inclusive DIS on nuclei, the Drell-Yan reaction, and heavy-ion collisions
all bring different kinds of information on parton propagation within a medium,
while the most direct information on hadron formation comes from the DIS data.
Over the next decade one can hope to begin to understand these data within a
unified picture. We briefly survey the most relevant data and the common
elements of the physics picture, then highlight the new Jefferson Lab data, and
close with a prospective for the future.
