Suelta editions of seventeenth-century Spanish plays traditionally have not taken into consideration the elaboration of critical editions of these plays, since they usually were not well catalogued or because they presented false attributions, dates or printers. However, during the last years this type of edition has been better studied and catalogued, and different editions and studies have pointed out how the best text of a determined play, or at least better readings of many verses, could have survived in these suelta editions. This paper focuses on the case of La puente de Mantible, by Calderón de la Barca, published in the reliable Primera parte of the playwright, but whose text can be widely improved thanks to an apparently very unreliable suelta edition of the play, with attribution to Lope de Vega.