  A review is given on the subject of hadron production at intermediate $p_T$
in heavy-ion collisions. The underlying dynamical processes are inferred from
interpreting the data in the framework of recombination. Ridge formation with
or without triggers is found to play an important role in nearly all
observables in that $p_T$ region. Correlation data would be hard to interpret
without taking ridges into account. The semi-hard partons that create the
ridges may even be able to drive elliptic flow without fast thermalization.
