I have a 1964 Roget's Thesaurus which I treasure above most of my wordly possessions. If the apartment were on fire, I'd toss the cat out the screendoor, and stuff the Roget's down my pants before I started grabbing valuables. ("Is that a thesaurus in your pants, or are you just happy to see me?") When I was in high school, the book gravitated toward my room, ending up there whenever I was hammering out a term paper the night before it was due, and it was one of the "house books" I took with me when I moved out (along with the complete Encyclopaedia Britannica, and the Durant's Story of Civilization). I claimed ownership by right of eminent domain. Sometimes, the needs of the few outweigh the needs of the many. Besides, the bookplate in the front of the Roget's is in my father's name: after the divorce, I had every right to claim it in his name.

I've looked at the new-fangled thesauri they hawk in bookstores these days. None can compete with this 40-year-old concordance for thoroughness, ease of use, or vocabulary. At 552 pages, I don't even need to keep a dictionary handy: almost everything is right here, at my fingertips (unless Scrabble is being played, which requires the big Random House, unabridged). As a matter of fact, I use the Roget's as a sort of portable writing desk when I'm writing on the couch. But for looking up definitions of uncommon and infrequently-seen words, I'd have to go with the Oxford Dictionary of Difficult Words. But then, I'm a bit of a wordsnob (I still lose at Scrabble, though).

As far as dictionaries are concerned, I have a simple rule of thumb I apply when shopping: the callipygous porphyry test. If a dictionary isn't large enough or complete enough to contain the words callypygous and porphyry, then it isn't worth its weight.