Item Specification: The Hitchhiker's TowelCopy Anchor Link

"A towel, it says, is about the most massively useful thing an interstellar hitchhiker can have. Partly it has great practical value — you can wrap it around you for warmth as you bound across the cold moons of Jaglan Beta; you can lie on it on the brilliant marble-sanded beaches of Santraginus V, inhaling the heady sea vapours; you can sleep under it beneath the stars which shine so redly on the desert world of Kakrafoon; use it to sail a mini-raft down the slow heavy river Moth; wet it for use in hand-to-hand combat; wrap it round your head to ward off noxious fumes or avoid the gaze of the Ravenous Bugblatter Beast of Traal (a mindbogglingly stupid animal, it assumes that if you can't see it, it can't see you — daft as a brush, but very very ravenous); you can wave your towel in emergencies as a distress signal, and of course dry yourself off with it if it still seems to be clean enough."

— The Hitchhiker's Guide to the Galaxy, Chapter 3

As chronicled in The Hitchhiker's Guide to the Galaxy, a towel is the single most essential piece of survival equipment in the known Universe. During his fifteen years on Earth, roving researcher Ford Prefect kept a largish bath towel from Marks and Spencer at the bottom of his leather satchel (beneath his Sub-Etha Sens-O-Matic, Electronic Thumb, Guide, a few biros, and a notepad).

Practical Value Across the GalaxyCopy Anchor Link

• Thermal Insulation: Wrap it around you for warmth as you bound across the cold moons of Jaglan Beta.
• Beachside Relaxation: Lie on it on the brilliant marble-sanded beaches of Santraginus V, inhaling the heady sea vapours.
• Bivouac Shelter: Sleep under it beneath the stars which shine so redly on the desert world of Kakrafoon.
• Nautical Propulsion: Use it to sail a mini-raft down the slow heavy River Moth.
• Close-Quarters Defense: Wet it for use in hand-to-hand combat.
• Atmospheric & Predator Shielding: Wrap it round your head to ward off noxious fumes or avoid the gaze of the Ravenous Bugblatter Beast of Traal on Traal.
• Signaling & Hygiene: Wave it in emergencies as a distress signal, and of course dry yourself off with it if it still seems to be clean enough.

Strag Psychological Impact & Hitch-Hiking SlangCopy Anchor Link

More importantly, a towel has immense psychological value:

• The Strag Assumption: For some reason, if a strag (strag: non-hitchhiker) discovers that a hitchhiker has his towel with him, he will automatically assume that he is also in possession of a toothbrush, face flannel, soap, tin of biscuits, flask, compass, map, ball of string, gnat spray, wet-weather gear, space suit, etc., etc.
• The Happy Loan: Furthermore, the strag will then happily lend the hitchhiker any of these or a dozen other items that the hitchhiker might accidentally have "lost." What the strag will think is that any man who can hitch the length and breadth of the galaxy, rough it, slum it, struggle against terrible odds, win through, and still know where his towel is is clearly a man to be reckoned with.
• Hitch-Hiking Slang: Hence a phrase which has passed into hitch-hiking slang, as in:

  "Hey, you sass that hoopy Ford Prefect? There's a frood who really knows where his towel is."

  • Sass: know, be aware of, meet, have sex with.
  • Hoopy: really together guy.
  • Frood: really amazingly together guy.