In the early 1620's the famous Spanish playwright, Don Pedro Calderón de la Barca, wrote a delightful and suspenseful comedia, The Fake Astrologer, which gained great favor and popularity all over Europe. In fact, there are at least eighteen adaptations of this play in French, English, Italian, Dutch, German, and Spanish, some by no lesser authors than John Dryden and Voltaire. The present work represents the complete «literary biography» of this much-traveled play, including the critical Spanish text, a faithful, modern, rhymed English translation, and a study of the adaptations. A critical appreciation of the comedia will allow the reader to understand how a typical baroque cloak and sword play of the Spanish Golden Age was transmuted to please audiences and readers with different national tastes and preferences. It is hoped that in its present modern English version and with its complete commentary it will prove of equal appeal to the aficionado of good theatre, the student of comparative literature, the Spanish Golden Age specialist, and the larger reading public.