Here's a cool book for anyone who speaks a bit of Spanish and would like to learn more. Las puertas retorcidas is a unique book aimed at upper beginning and intermediate students. In fact, it is so unique that it's rather difficult to categorize, because it's all of the following rolled into one:

 - Bilingual book (Spanish-English)
 - Grammar book
 - Audio book

Illustrated with three dozen Victorian-like black-and-white illustrations. Las puertas retorcidas is a mystery story, each chapter of which contains a passage from the book, in Spanish and English; an audio track of the Spanish passage; a list of tricky vocabulary; a grammar lesson (mainly verbs and idiomatic expressions); and a grammar quiz with answers.

The first 12 chapters cover basic Spanish grammar in short, easy passages. From chapter 13 on, the story passages get progressively longer and more difficult, and the grammar lessons are very cleverly incorporated into the story itself. For example, in order to open locked doors, the protagonists have to recite certain vocabulary lists or verb conjugations that were discussed in earlier chapters. In the last chapters of the book, a thorough grammar and vocabulary review is woven into the story. Instructions within each chapter are written in a friendly yet distinctly professorial style. A Spanish-to-English vocabulary list/index completes the book.

On the audio CD, a native Spanish speaker dramatically recites the Spanish with a different voice for each character. The narrator's recitation is clear and fairly slow - intermediate speakers shouldn't have any trouble understanding.

For more detailed information, read my full review or visit the author's website.

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