The case for an abundant population of feeble galaxies at z>8

We present new observational constraints on the abundance of z>8 Lyman-alpha emitters secured from a deep Keck near-infrared spectroscopic survey utilizing the strong magnification provided by lensing galaxy clusters. The survey has yielded six promising candidate Lyman-alpha emitters which appear to lie between z=8.7 and z=10.2. We describe detailed follow-up exposures made to secure the high-redshift interpretation, as well as further tests that are currently underway with new instrumentation. Based upon our current knowledge of these sources, we discuss their possible contribution to the reionization of neutral hydrogen.