Just as certain innocuous American expressions, like ""fanny pack,"" should never be used in London, certain Spanish words, like ""coger,"" are perfectly acceptable in Madrid and perfectly vulgar in Buenos Aires. So when picking a Spanish-English dictionary, it's important to choose one that clearly indentifies variations in regional usage. The three titles reviewed here all have a comprehensive, unabridged range of entries, which include cross-referencing and phonetic spellings and definitions that range in length from three lines to two pages. They all provide a thorough summary of Spanish and English grammar, with tables of irregular verbs. Most importantly, they all handle issues of usage with clarity and sensitivity. Of the trio, the Larousse is the best known. It's certainly the most exhaustive reference on idiomatic and technical expressions. The Larousse consistently distinguishes between Latin American and Peninsular usage, though its definitions do lean towards Spain and Britain. Its translation of ch vere, for example, as ""brilliant"" might lead some American readers to believe the word connotes a degree of intelligence, when, in fact, its meaning is closer to ""super"" or ""fantastic."" In a particularly notable gaffe, the Larousse's entry on bano doesn't contain the word ""bathroom"" though that's how the word is used most often in Latin America because in Spain the term for ""restrooms"" is los servicios. The Oxford does a better job of distinguishing between British and American diction (its entry on bano goes so far as to outline the distinctions among ""bathroom,"" ""lavatory,"" ""loo,"" and ""washroom""), and its explanations of the language variations within Latin America are more specific than the Larousse's. Guagua, it lets you know, is an informal word for ""baby"" in the Andes region and a slang term for ""bus"" in Cuba and the Canary Islands. (The Larousse groups both these meanings under the more general heading ""American usage."") The Oxford also contains useful boxes that cluster words by topic (colors, the human body, etc.), as well as a glossary explaining cultural terms that don't have simple translations, such as ""Mason-Dixon Line"" and sobremesa (the time spent drinking and talking around a table after a meal is finished). Like the Oxford, the Harper Collins dictionary contains notes on cultural topics, and it also provides country-specific guidelines for usage in Latin America. Though its layout is the least elegant of the three, the Harper Collins provides the strongest coverage of Latin American slang. For example, it's the only dictionary we reviewed that gave all the various meanings of perico, a curious word that, depending on the context and location, can mean parakeet, toupee, cocaine, milky coffee, or scrambled eggs with fried onions. Such impressive thoroughness has made the Harper Collins dictionary a favorite among academics specializing in Latin American studies. The Harper Collins dictionary also goes a step further than grammar review with its ""Language in Use"" section, which presents a painstaking introduction to business writing style in both English and Spanish. This section, which helps readers find equivalents for such hard-to-translate expressions as Me he enterado con gran tristeza de la muerte de tu..."" for ""I was very sad to learn of the death of...,"" teaches users how to phrase a job application letter, how to pronounce an e-mail address, and how to draft an official apology, among other business necessities. A good Spanish-English dictionary should help readers navigate complex regional differences. All these dictionaries do this quite well, but the Harper Collins should be the first choice among libraries. Larger libraries would do well to offset the Harper Collins's deficiencies in Cervantes-style Spanish by purchasing a copy of the Larousse as well, and those seriously interested in linguistic variations may want to add the Oxford, which does the best job charting the differences between British and American English. Marcela Valdis, ""Criticas"".