1. INTRODUCTION  
2. OBSERVATION AND DATA REDUCTION  
3. TARGET SELECTION  
4. SPECTROSCOPY  
5. COMPLETENESS  
6. CONSTRAINT ON THE QUASAR LUMINOSITY FUNCTION  
7. DISCUSSION  
7.1. The Quasar Candidates  
7.2. The BH Mass of Faint High $z$ Quasars  
7.3. Reionization  
8. CONCLUSION