Subsequently, motivated, a series of surveys have been conducted using Hubble Space Telescope 's Cosmic Origins Spectrograph (HST /COS) to measure the LyC directly. These efforts culminated in the Low-redshift Lyman Continuum Survey, a large HST /COS program which nearly tripled the number of direct measurements of the LyC from dwarf galaxies. To date, at least 50 LCEs have been confirmed using HST /COS with LyC escape fractions anywhere from ≈ 0 to 88%. The results from the Low-redshift Lyman Continuum Survey have provided the empirical foundation necessary to identify and understand LCEs at the Epoch of Reionization. With new observations from JWST, populations of LCEs are now being studied at cosmological redshifts greater than 6, allowing for the first time a detailed and direct assessment of the origins of cosmic Reionization. Combining these large samples of galaxies with new constraints on the UV luminosity function indicates that dwarf galaxies overwhelmingly contribute to Reionization.