A scientist who, 18 months before the start of the novel, took an expedition to the North to presumably study Dust and, Lord Asriel believes, the city that's visible through the Aurora. Things went wrong, however: Lord Asriel shows Dr. Grumman's scalped head to the Scholars at Jordan College and implies that either the panserbjørne or the Tartars killed him. Lee Scoresby later suggests that this is false, and that Dr. Grumman is alive—or, at least, wasn't killed by the Tartars, since Dr. Grumman was an "honorary Tartar" and participated in their spiritual rituals.
Dr. Grumman Character Timeline in The Golden Compass
The timeline below shows where the character Dr. Grumman appears in The Golden Compass. The colored dots and icons indicate which themes are associated with that appearance.
...asks if this is the "Barnard-Stokes business." Lord Asriel addresses a Scholar and says that Grumman was probably investigating this phenomenon, but Grumman is dead. As proof, he opens one of... (full context)