Rolf-Peter Kudritzki
                 
                    Universit\"atssternwarte M\"unchen
                 
                   " Extragalactic Stellar Astronomy "
                   
Abstract.

The spectral analysis of the most luminous stellar objects as individuals 
provides a unique tool to investigate the properties of young populations in 
galaxies. In this way, kinematics, abundances, abundance gradients and 
distances of galaxies can be determined. Two groups of objects, blue
supergiant stars and Planetary Nebulae are discussed.

It is shown how the parameters of the most luminous {\bf blue supergiants} 
(temperature, gravity, radii, luminosities, masses, mass-loss rates, wind 
velocities, abundances) in different galaxies are measured using spectral 
information from the UV to the IR. Recent results for O, B, A-supergiants in 
the Galaxy, LMC, SMC, M31, M33, NGC 6822 and beyond the Local Group are 
presented. Special emphasis is given to the {\bf Wind Momentum -- Luminosity 
Relationship} as a tool for the determination of extragalactic distances out 
to the Virgo and Fornax clusters of galaxies. 

{\bf Planetary Nebulae} detected in galaxies by interference 
filter techniques are discussed as distance indicators and tools to investigate
the kinematics and gravitational potential of galaxies. The population
of intracluster PN detected recently between the galaxies of the Virgo cluster
is discussed. Multi-object spectroscopy carried out with FORS at the ESO VLT 
is presented showing that a significant fraction of these objects are
extreme Lyman-alpha emitters at high redshift. Population synthesis of the
ionizing radiation applying hydrodynamic NLTE model atmospheres with stellar 
winds is used to constrain stellar masses, starformation rates and chemical
composition of the ionizing stellar population in these galaxies.