On The Detection and Overthrow of The So-Called Gnosis

On the Detection and Overthrow of the So-Called Gnosis, today also called On the Detection and Overthrow of Knowledge Falsely So Called (Greek: ἔλεγχος και άνατροπή της ψευδωνύμου γνώσεως, lit. "Elenchus and Overturning of the Pseudonymous Knowledge"), commonly called Against Heresies (Latin: Adversus haereses, Greek: κατὰ αἱρέσεων), is a five-volume work written by St. Irenaeus in the 2nd century. The final phrase "of knowledge falsely so-called" (Greek: tes pseudonymou gnoseos genitive case; or nominative case pseudonymos gnosis) is a quotation of the apostle Paul's warning against "knowledge falsely so-called" in 1 Timothy 6:20.

Due to its reference to Eleutherus as the current bishop of Rome, the work is usually dated c. 180. In it Irenaeus identifies and describes several schools of gnosticism and contrasts their beliefs with what he describes as catholic, orthodox Christianity. Only fragments of the original Greek text exist, but a complete copy exists in a wooden Latin translation, made shortly after its publication in Greek, and Books IV and V are also present in a literal Armenian translation.