Originally published in 1971, this was the first critical edition of La fianza satisfecha, a play of disputed authorship dating from the Golden Age of Spanish literature. The editors of this edition believe it was written in 1614 by Lope de Vega. Their reasons, which rely on similarities with Lope's other plays and on relationships between Lope and Tirso de Molina, are presented in the introduction, which also discusses the fourteen texts used to establish this text, the literary parallels, two scrutinies of this play by the Inquisition, and contemporary criticism and interpretation. The hero of la fianza satisfecha, Leonido, is represented as a perverse monster carrying out every possible atrocity against family, society and religion who, in the last act, finally embraces Christianity and repents his sins.