  We report the detection of four images in the recently discovered lensed QSO
RX J0911.4+0551. With a maximum angular separation of 3.1", it is the quadruply
imaged QSO with the widest known angular separation. Raw and deconvolved data
reveal an elongated lens galaxy. The observed reddening in at least two of the
four QSO images suggests differential extinction by this lensing galaxy. We
show that both an ellipticity of the galaxy (epsilon_{min}=0.075) and an
external shear (gamma_{min}=0.15) from a nearby mass has to be included in the
lensing potential in order to reproduce the complex geometry observed in RX
J0911.4+0551. A possible galaxy cluster is detected about 38", from RX
J0911.4+0551 and could contribute to the X-ray emission observed by ROSAT in
this field. The color of these galaxies indicates a plausible redshift in the
range of 0.6-0.8.
