Hippocrene publishes several dozen "concise dictionaries" and most of these get ratings of one or two stars from readers. They seem to specialize in what some might call the more "exotic" or "unusual" languages, such as Sicilian, Uzbek, Twi, Sanskrit, Macedonian, Nepali and in this case Nahuatl. (None of the dictionaries I have listed have an average customer rating higher than two stars.) These books are not concise, and are arguably not even dictionaries, because for example, the Nahuatl-English/English-Nahuatl (Aztec) dictionary lacks any type of critical apparatus or source material commonly found in dictionaries. Also, as the previous reviewer pointed out we do not know whether this is a dictionary of Classical Nahuatl or of current Nahuatl dialects. My guess it's a combination of the two, which makes matters even more confusing. The small 6'' x 4" x 1" format suggests that these books are to be carried in the pockets of travelers and that they be used as guides, so that words such as airplane, polishing machine, crocodile, and observatory can be said to the "natives" when traveling in rural Veracruz, Tlaxcala or San Luis Potosi.
But the book is not completely useless, it is the only dictionary with an English-Nahuatl section and when used in conjunction with the dictionaries by Karttunen or Molina it can be helpful for translation. The back of the book also contains a reference section with every day phrases, numbers, parts of the body, animals, colors etc. but as with the English-Nahuatl section this needs to be used with extreme caution. Unless you have other dictionaries do not rely on this book.
Review by Walter O. Koenig