Mattisyahu Yechezkel Gutman was a Torah scholar who corresponded with the Rebbe in the 1950s about scholarly and publishing matters. No reliable published biography is available; the summary below is drawn from the letters themselves.
Many of the Rebbe's letters concern scholarly method and publishing: thanks for Aggados Talmud Yerushalmi, which he sent, with notes on its indexing (IK 3367); adding source references and an index to chassidic works (IK 2142); citing sources for chassidic teachings in published works (IK 2754); the name of the Baal Shem Tov's daughter, and editorial notes (IK 2315); and guidance on manuscripts (IK 7233). The Rebbe wrote that when no one else will print Chabad seforim, we must (IK 4186), and blessed him to increase and strengthen Torah (IK 2490). One letter discusses desire and financial ability as human traits (IK 2111).
See also: Jewish outreach – Publishing and spreading Torah books; Accuracy – Torah texts and editions; Accuracy – Chassidus manuscripts.