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We present UBV color magnitude diagrams (CMDs) for the globular cluster M4.The CMDs show a sequence of four luminous blue stars (V<20, U-V<-0.6) whichappear to be cluster hot subdwarfs. We present spectra for the three brightestones. We also note the presence of a population of faint blue objects, likelyto be hot, young white dwarfs (WDs) belonging to the cluster. We have selectedfive objects above V=22 mag, bright enough for follow-up ground-basedspectroscopy and present their coordinates and finding charts. We show aspectrum for variable V46 (Kaluzny et al. 1997) which suggests that it is a hotsubdwarf, along with a new light curve obtained with the ISIS image subtractionpackage (Alard 2000). The light curve is unstable, but only one period ofvariability is apparent. Two new variables have been discovered, both locatedon the cluster red giant branch (RGB). We also present a differential E(B-V)reddening map and a fiducial sequence for the main sequence, subgiant branchand red giant branch on the V/B-V CMD for a selected region with uniformreddening. Based on a comparison with the M5 fiducial sequence we obtain areddening estimate of E(B-V)=0.41 mag towards M4, consistent with previousdeterminations.Comment: 16 pages LaTeX, 14 PostScript figures, 5 tables, major revisions,  accepted to A

Clusters Ages Experiment: Hot Subdwarfs and Luminous White Dwarf Candidates in the Field of the Globular Cluster M4