  Wolf-Rayet (WR) galaxies provide detailed information on massive star
populations in starbursts and thereby represent ideal objects to determine
accurate ages for young systems, to measure the burst duration, and to probe
the upper end of the IMF. WR galaxies play also a particular role in a variety
of studies on star formation in Seyfert2/LINERS, dust production and local
chemical enrichment, temperature fluctuations in HII regions, gaz outflows and
X-ray emission etc.
  Different age indicators for young starbursts and WR galaxies are discussed.
We summarise recent work on the burst properties of WR galaxies, massive star
populations at different metallicities, and the use of WR galaxies as
benchmarks for multi-wavelength models of starbursts and photoionisation models
including IR fine structure lines.
