The SDSS is a project to image 1/4 of the sky (about 10,000 square degrees) above galactic latitude 30 degrees in five optical bands, u', g', r', i' and z', to a depth of about 23 mag in the sensitive bands, and to obtain spectra of a million galaxies and 100,000 quasars selected from the imaging data. At this writing, the SDSS is nearing the end of commissioning and will shortly begin its 5 years of operation.

A number of significant results have already been obtained from the imaging commissioning data, ranging from measurements of anomalous refraction in the Earth's atmosphere to the highest redshift quasars found to date; these illustrate the enormous potential of the SDSS to make fundamental contributions across the astronomical board. Particular emphasis in this talk will be laid on SDSS discoveries of objects close to and below the main sequence hydrogen burning limit.