In the winter of 1942, the sixth Lubavitcher Rebbe, Rabbi Yosef Y. Schneersohn, of righteous memory, gave his son-in-law, the future Rebbe, Rabbi Menachem Mendel Schneerson, of righteous memory, the task of compiling an anthology of Chasidic aphorisms and customs arranged according to the days of the year.

The calendar was entitled Hayom Yom. In describing this work Rabbi Yosef Yirzchak wrote: …"A book that is small in format…but bursting with pearls and diamonds of choicest quailty." "A splendid palace of Chasidism." True to these words, Hayom Yom has become a beloved classic work and a source of daily spiritual sustenance.