(ἀποκρυφά, sc. βαβλά, hidden, secreted, mysterious), a term in Theology, applied in various senses to denote certain books claiming a sacred character. It is first found in this use in Clemens Alexandrinus, Stromata, 13, c. 4, ἐκ τῶν ἀποκρυφῶν.

In the early ages of the Christian Church this term was frequently used to denote books of an uncertain or anonymous author, or of one who had written under an assumed name. Its application, however, in this sense is far from being distinct, as, strictly speaking, it would include canonical books whose authors were unknown or uncertain, or even pseudepigraphal.

In the Bibliothèque Sacrée, by the Rev. Dominican Fathers Richard and Giraud (Paris, 1822), the term is defined to signify—1st, anonymous or pseudepigraphal books; 2d, those which are not publicly read, although they may be read with edification in private; 3d, those which do not pass for being composed by a sacred author or an apostle, as the Epistle of Barnabas; and, 4th, dangerous books composed by ancient heretics to favour their opinions. They also apply the name "to books which, after having been contested, are put into the canon by consent of the churches, as Tobit," &c. And Jahn applies it in its most strict sense, and that which it has borne since the fourth century, to books which, from their inscription, or the author's name, or the subject, might easily be taken for inspired books, but are not so in reality. It has also been applied, by Jerome, to certain books not found in the Hebrew canon, but yet publicly read from time immemorial in the Christian church for edification, although not considered of authority in controversies of faith. These were also termed Ecclesiastical Books, and consisted of the Books of Tobit, Wisdom, Ecclesiasticus, Baruch, the first two Books of Maccabees, the last seven chapters (according to Cardinal Hugo's division) of the Book of Esther, and those (so called) parts of the Book of Daniel which are not found in Hebrew, viz., the Song of the Children, the Speech of Azariah, the History of Susannah, and the Fable (as Jerome calls it) of Bel and the Dragon. These have been denominated, for distinction's sake, the deuterocanonical books, inasmuch as they were not in the original or Hebrew canon. In this sense they are called by some the Antilegomena of the Old Testament. "The uncanonical books," says Athanasius, or the author of the Synopsis, "are divided into antilegomena and apocrypha."

Among spurious and Apocryphal Books, as distinct from Antilegomena or Ecclesiastical, are doubtless to be considered the Third and Fourth Books of Esdras; the Book of Enoch; the Testament of the Twelve Patriarchs; the Assumption of Moses, &c. These books were all known to the ancient fathers; and, although incontestably spurious, are of considerable value from their antiquity, as throwing light upon the religious and theological opinions of the first centuries. The most curious are the Third and Fourth Books of Esdras, and the Book of Enoch, which has been but recently discovered, and has acquired peculiar interest from its containing the passage cited by the apostle Jude.

Most of the apocryphal Gospels and Acts noticed by the fathers, and condemned in the catalogue of Gelasius, are generally thought to have been the fictions of heretics in the second century, and have long since fallen into oblivion. Of those which remain, although some have been considered by learned men as genuine works of the apostolic age, the greater part are universally rejected as spurious, and as written in the second and third centuries. A few are, with great appearance of probability, assigned to Lucius Clarinus, supposed to be the same with Leontius and Seleucus, who was notorious for similar forgeries at the end of the third century. The authorship of the Epistle of Barnabas is still a matter of dispute; and there appear strong grounds for believing the charge made by Celsus against the early Christians, that they had interpolated or forged the ancient Sibylline Oracles.

But, whatever authority is to be ascribed to these documents, it cannot be denied that the early church evinced a high degree of discrimination in the difficult task of distinguishing the genuine from the spurious books. "It is not so easy a matter," says the learned Jeremiah Jones, "as is commonly imagined, rightly to settle the canon of the New Testament. For my own part, I declare, with many learned men, that in the whole compass of learning I know no question involved with more intricacies and perplexing difficulties than this." (New and Full Method, vol. i. p. 15.)

Testimony and tradition are the principal means of ascertaining whether a book be canonical or apocryphal. Inquiries of this kind, however, must of necessity be confined to the few. The mass of Christians, who have neither time nor other means of satisfying themselves, must confide, in questions of this kind, either in the judgment of the learned, or the testimony at least, if not the authority, of the church.

The following are the principal apocryphal (or spurious) books of the Old Testament, which have descended to our times. The greater number of them can scarcely be considered as properly belonging to the Apocrypha of the Old Testament, as they have been most probably written since the Christian era, and not before the second century:—Third and Fourth Esdras, the Book of Enoch, the apocryphal Book of Elias the Prophet, the Third, Fourth, and Fifth Books of Maccabees (received by the Greek Church), the Ascension of Isaiah, the Assumption of Moses.

Of the New Testament, the following are the extant spurious Gospels:—The History of Joseph the Carpenter, which has been preserved in the East in an Arabic translation. The Gospel of the Infancy; the Gospel of Thomas the Israelite; the Protevangelion of James; the Gospel of the Nativity of Mary; the Gospel of Nicodemus, or Acts of Apocryphus Pilate. Besides these, many are cited by the fathers which no longer exist.

Of spurious writings of the nature of Acts of Apostles the following are extant:—The Creed of the Apostles; the Recognitions of Clement, or the Travels of Peter; the Shepherd of Hermas; the Acts of Paul, or the Martyrdom of Thecla; Abdia's History of the Twelve Apostles; the Constitutions of the Apostles; the Canons of the Apostles; the Liturgies of the Apostles. Of spurious Epistles.—The Epistles of Barnabas, Clement, Ignatius, and Polycarp; the Epistle of Paul to the Laodiceans; the Third Epistle of Paul to the Corinthians; the Epistle of Peter to James; the Epistles of Paul and Seneca.

Besides these many other pretended sacred writings were palmed upon the world, of which the titles alone are preserved, and probably many more of which the very names have perished. See Fabricii Codex Pseudepigraphus V. T., 1713 and 1741, and Codex Apocryphi N. T., 1713-1722; Auctarium Codicis Apocryphi N. T. Fabriciani, editio And. Birch, 1804. A New and Full Method of Settling the Canon of the N. T., by the Rev. Jeremiah Jones, 1827. Du Pin, Prolegomena, 1701, and Canon of the Old and New Testaments, 1700; and Codex Apocryphi N. T., opera et studio T.C. Thilo, tom. i., Lips, 1832, 8vo.