Some people put thesauruses in a category with the pegasuarus–that is, extinct. But not me! The thesaurus (the one on my bookshelf, not the one in Microsoft Word) is my favorite tool. Why? because I’m an absolute fiend about finding the right word, and I need help to do it.
Be aware of the difference between “Roget’s style” and “dictionary style” thesauruses or “synonym finders.” The latter two are arranged alphabetically; the former uses an index in the back and numbered entries in the front. A Roget’s involves multiple steps (looking up a word in the back index, and then turning to various ones of the numbered citations), but yields many more possible synonyms and will inspire you to find the perfect word.
As with dictionaries, the key is to go with a reliable publisher, in addition to finding a Roget’s style thesaurus. (I’ve got Roget’s International Thesaurus on my shelf. Bartlett’s Roget’s Thesaurus is also reputable, as are volumes published by Oxford Dictionaries or Merriam-Webster’s.)
Beware digital thesauruses. The one in Microsoft Word is practically worthless, as is Thesaurus.com. But I’m a fan of Thinkmap’s Visual Thesaurus, which may not get you quite as many synonyms as Roget’s, but displays them in a cool astronomical way–i.e., as little constellations of meaning. (It helps that its executive producer, Ben Zimmer, is a respected lexicographer.) It costs about $3 per month or $20 per year to subscribe.
A follower turned me on to Visuwords.com, a free alternative. Like Thinkmap’s version, Visuwords displays words in web-like diagrams that provide an interactive way to find synonyms and view relationships between words. It does it in pretty colors, too!