The hyttebok is the handwritten guestbook kept at every DNT cabin in the Norwegian mountain network. The book lives on a small shelf or table in the common room and is filled in by every party that stays the night: names, the date, the route walked in, the route planned for the next day, brief weather and condition notes, and any observation that might help the next party. The convention is genuinely useful - a hyttebok entry from the previous evening is often the most current available information on the state of the trail ahead.
The cultural register of the hyttebok is distinctive. Norwegian walkers tend to write briefly and practically - came in from Glitterheim, six hours, the high pass holds a soft snowfield, head north of the marked line - rather than at length. International visitors sometimes write longer, more reflective entries; this is also fine, and the books accumulate a quiet polyglot record of mountain weeks across decades. The oldest active hyttebøker at the major staffed lodges go back to the 1950s; the books themselves are archived in the DNT central library when they fill up.
The serious function of the hyttebok is route planning. On any multi-day trip, the standard practice is to read the previous five to ten parties's entries on arrival at the cabin, particularly any entries from the route you plan to walk the next day. Conditions in Norwegian mountain country can shift substantially across a 24-hour weather front, and a hyttebok entry from the morning of the same day is genuinely useful intelligence. The corresponding obligation - to write your own entry before leaving the next morning - is taken seriously by experienced walkers.