1 INTRODUCTION  
2 BASELINE DATA ON PRESENT-DAY S0 GALAXIES  
3 CLASSIFICATION OF PRESENT-DAY S0 GALAXIES FROM THEIR OPTICAL SPECTRA  
4 INFRARED DETECTIONS OF PRESENT-DAY S0 GALAXIES  
5 RADIO AND X-RAY DETECTIONS OF PRESENT-DAY S0 GALAXIES  
6 SUMMARY  