  Concurrent observations of Lyman continuum (LyC) and Lyman-alpha (Lya)
emission escaping from star-forming systems at low redshift are essential to
understanding the physics of reionization at high redshift (z >~ 6). Some have
suggested reionization is dominated by numerous small galaxies with LyC escape
fractions f_e ~ 10%, while others suggest mini-quasars with higher f_e might
also play a role. At z > 3, direct observation of LyC leakage becomes
progressively more improbable due to the increase of intervening Ly limit
systems, leaving Lya as the primary diagnostic available to the James Webb
Space Telescope for exploring the epoch of reionization. If a quantitative
relationship between escaping LyC and Lya emission can be established at low z,
then the diagnostic power of Lya as a LyC proxy at high z can be fully
realized. Past efforts to detect f_e near z ~ 3 have been fruitful but
observations at low redshift have been less so. We discuss the sensitivity
requirements for detecting LyC leak in the far- and near-UV as a function of
redshift 0.02 < z ~< 3 and f_e >= 0.01 as estimated from UV luminosity
functions. UV observations are essential to understanding of the physics of LyC
escape and the ultimate goal of identifying the source(s) responsible for
reionization.
