THE EXPERIMENT FOR CRYOGENIC LARGE-APERTURE INTENSITY MAPPING (EXCLAIM) IS A HIGH-ALTITUDE BALLOON SPECTROMETER DESIGNED TO DEEPEN OUR UNDERSTANDING OF STAR FORMATION IN A COSMOLOGICAL CONTEXT. IT WILL MAP THE SUB-MM EMISSION OF REDSHIFTED CARBON MONOXIDE (CO) AND SINGLY-IONIZED CARBON ([CII]) LINES IN WINDOWS COMPRISING 0<Z<3.5. THESE LINES TRACE THE PRECURSORS OF STAR FORMATION BUT HAVE ONLY PRELIMINARY CHARACTERIZATION BEYOND THE NEARBY UNIVERSE WITH MOST PREVIOUS EFFORTS LIMITED TO THE BRIGHTEST OBJECTS OR GALAXIES SELECTED IN OTHER SURVEYS. RATHER THAN DETECT INDIVIDUAL GALAXIES EXCLAIM WILL MEASURE THE STATISTICS OF BRIGHTNESS FLUCTUATIONS OF REDSHIFTED CUMULATIVE LINE EMISSION. THIS APPROACH IS KNOWN AS INTENSITY MAPPING AND THE ENDURING QUESTS DARING VISIONS ROADMAP ESTABLISHES IT AS A PRIORITY IN THE VISIONARY ERA TO "COMPLETELY MAP THE CONTENT OF SELECTED VOLUMES OF SPACE THAT REPRESENT SLICES THROUGH ALL OF COSMIC TIME." EXCLAIM IS A PATHFINDER TO FUTURE MISSIONS THAT WILL PROBE EARLY STAR FORMATION AND REIONIZATION. A BLIND COMPLETE CENSUS OF REDSHIFTED CO AND [CII] ADDRESSES NEW WORLDS NEW HORIZONS DECADAL SURVEY PRIORITIES TO UNDERSTAND BARYONS IN GALAXIES AND THE CONTEXT OF THEIR DARK MATTER HALOS.