Spectral Monitoring of Mrk 421 during 2004
  Daily monitoring of Mrk 421 in the X-ray and TeV bands during the first half of 2004 showed rapid flaring events above an elevated base flux level, culminating from March to May 2004 at an average flux level matching the highest detected flux state in 2001. Here we summarise the daily X-ray spectral variability observed with the RXTE-PCA instrument. We also explore the X-ray and TeV gamma-ray connection from near simultaneous data obtained using the Whipple 10m Cherenkov imaging telescope. 
J. Grube (for the VERITAS Collaboration)