KECK HIRES spectroscopy of APM 08279+5255

With an optical R-band magnitude of 15.2, the recently discovered z = 3.911 broad absorption line quasar APM 08279+5255 is an exceptionally bright hig h-redshift source. Its brightness has allowed us to acquire a high signal-t o-noise ratio (similar to 80), high-resolution (similar to 6 km s(-1)) spec trum using the HIRES echelle spectrograph on the 10 m Keck I telescope. Giv en the quality of the data, these observations provide an unprecedented vie w of associated and intervening absorption systems. Here we announce the av ailability of this spectrum to the general astronomical community and prese nt a brief analysis of some of its main features.