Abstract
Observations over the past 20 yrs or so are reviewed, with emphasis on recent high spatial resolution observations. The results lend support to earlier ideas on the propagation of type III electron streams through coronal regions of weak magnetic field strength but have not as yet settled the question whether the electrons propagate along the axes of coronal streamers. Several important burst properties appear to be significantly affected by ray scattering on small-scale size density irregularities in the corona.