B. Netanyahu, one of the world's foremost medievalists, has made a lifelong project of studying the historical evolution of Marranism and seeking to ascertain the genesis of the Spanish Inquisition. In this seminal work, which opened an ongoing debate on the nature of conversion and belief in late medieval Spain, Netanyahu analyzes evidence on the Marranos contained in the Hebrew sources.

For this new edition, the author has updated the book and added an Afterword in which he considers some of the scholarly reactions to the work since the publication of the first edition in 1966. "This book's revolutionary thesis dispels the romanticized heroic image of the Marrano found in Jewish literary and historical annals," says Isaac Barzilay, Professor Emeritus at Columbia University. "Netanyahu's conception of the Marranos is of a people whose majority hardly resisted assimilation to Spanish culture and Christianity. Consequently, he unhesitatingly rejects the Inquisition's claim that it was established for the sole purpose of preserving the integrity of Christianity against the undermining effects of Marranism."