"Of what avail is a candle by day?" None whatsoever if the day were really day. But what if the day were really night in disguise? Then, if that candle could penetrate beyond the veneer of day, what could it not do with the night it so illuminated? The Mussar modules in A Candle by Day are designed to illuminate some of the pseudo-day in which we live by helping "the heart feel what the mind understands." The modules, all original, are arranged alphabetically by topic and within topic for ease of reference and recall.