According to EW, the cause of death was respiratory failure.
On Joss Whedon’s Firefly and its cinematic spinoff Serenity, Glass played the avuncular and spiritual Shepherd Derrial Book.
In S.H.I.E.L.D., Glass portrayed Dr. Streiten, a scientist in the loop on Phil Coulson’s mysterious return from the dead.
But Glass is probably best known for playing Detective Ron Harris in the New York police sitcom Barney Miller, which ran from 1975-82 on ABC.
