Author of "A Little Child" Mack & Lincoln Hall founded the Hall-Mack Company music publishing house (later bought by the Rodeheaver Company). Mack’s works include:
Boundless Love (Philadelphia, Pennsylvania: Hall-Mack Company, 1896)
The Service of Praise, with Lincoln Hall et al. (Philadelphia, Pennsylvania: Hall-Mack Company, 1900)
http://www.hymntime.com/tch/bio/m/a/c/mack_ih.htm
Irvin H. Mack