Most dungeons are dark. Elves and dwarves can see 60 feet in the dark, as can all monsters (and this term embraces all evil characters of the Dungeon Master), but humans and halflings will need artificial light or be reduced to half speed or less.Now, students of the LBBs (or even Philotomy's musings) will know that this ruling is not unique to Holmes. It's derived from Volume 3 of OD&D, where it's stated that
In the underworld some light source or an infravision spell must be used. Torches, lanterns and magic swords will illuminate the way, but they also allow monsters to "see" the users so that monsters will never be surprised unless coming through a door. Also, torches can be blown out by a strong gust of wind. Monsters are assumed to have permanent infravision as long as they are not serving some character.Still, it's an interesting conceit, namely, that simply by inhabiting a dungeon, monsters, including human adversaries, gain the ability to "see in the dark." Notice how what OD&D calls "infravision," Holmes (generally) calls by a very prosaic name. Indeed, Dr. Holmes is on record (in Dragon #52) as disliking the pseudo-scientific, naturalistic explanation of infravision. This makes me think that the scant and inconsistent references to infravision in Holmes were not original to his text but foisted on him Gygax or someone else at TSR.
This brings me to my final point. A lot of people tend to view the Holmes rulebook as a an introduction to AD&D, a position the rulebook itself seems to imply at various point and one I held as a younger person. However, in re-reading it, I grow ever more convinced that Holmes is better understood as an introduction to OD&D, which shouldn't really be a surprise if one has read Holmes's preface to his work. Seen in this light, I think Holmes becomes even more interesting and I'll have some more thoughts along this line in the days to come.