Of all the canonical and apocryphal confusions to be found in the transmition of the Bible, none is worse than the collection of books which are attached to the scribe Ezra
For most, when you open a Bible you will see but one book called the Book of Ezra. The book immediately following is called the Book of Nehemiah. However, if one were to take a look at the Greek Septuagint, you will find 1 Ezra, 2 Ezra, and 3 Ezra. And if you look at the Latin Vulgate, you will find 1 Esdras (Ezra), 2 Esdras, 3 Esdras, and 4 Esdras, but the numbers don't refer to the same books as the Greek numbering.
To begin with, the book of Ezra found in the modern English bible is the 2 Ezra of the Septuagint, and the 1 Ezra of the Vulgate; in the oldest manuscripts, the Septuagint's 2 Ezra also contains Nehemiah. Nehemiah is 3 Ezra to later editions of the Septuagint, 2 Esdras of the Vulgate.
The Greek text 1 Ezra, which is not part of Hebrew scripting (having been written in Greek), containts not only the 2/3 Ezra (i.e. the books of Ezra and Nehemiah), but begins at 2 Chronicles 35:1, adding the story of a contest in the court of Darius, and (with the exception of skipping Ezra 4:6, continues, containing 2/3 Ezra.
Now, in the Vulgate this text is called 3 Esdras and is only included in the appendix. In English texts, however, it is called 1 Esdras (while what the Vulgate calls I Esdras is called simply Ezra in English).
What of 4 Esdras? It is not, nor has likely ever been a canonical work. It doesn't appear in the Septuagint; the work is actually three seperate works, sometimes called 4, 5, and 6 Ezra, all written between the first and third centuries of the Common Era. In those English bibles which provide, it is called 2 Esdras; the Vulgate called if 4 Esdras, and included it in the appendix.
4 Ezra (4 Esdras 3-14) is often called the Apocalpyse of Ezra; it is a Jewish work, usually dated to the first century, and it tells of how the angel Uriel appears to Ezra and tells him of the great things God is about to do for Israel; this was probably written under the influence of the well-documented first-century political turmoil regarding Israel's rule by Rome.
5 Ezra (4 Esdras 1-2), though at the beginning of the book, is a later is a Christian work of the second century; it "prophecies" God's rejection of Israel and replacement by the Christians.
6 Ezra (4 Esdras 15-16) is also a Christian work, this one prophecying doom and persecution of the Church, and detailing how to endure. 6 Ezra is interesting, as it appears to have been quoted by Saint Gildas in his De Excidio Brittaniae et Conquestu (540 CE):
60. Hear ye moreover what blessed Esdras, that cyclopaedia of the divine law, threateneth in his discourse. "Thus saith our Lord God: My right hand shall not be sparing upon sinners, neither shall the sword cease over them who spill the innocent blood on the earth. Fire shall proceed from out of my wrath, and devour the foundations of the earth, and sinners as if they were inflamed straw. Woe be unto them who offend, and observe not my commandments, saith our Lord, I will not forbear them. Depart from me ye apostatizing children, and do not pollute my sanctuary. God doth know who offend against him, and he will therefore deliver them over to death and to slaughter. For now have many evils passed over the round compass of the earth. [6 Ezra 15:21-27] A sword of fire is sent out against you, and who is he that shall restrain it? shall any man repulse a lion that hungereth in the wood? or shall any one quench out the fire when the straw is burning? our Lord God will send out evils, and who is he that shall repress them? and fire will pass forth from out of his wrath, and who shall extinguish it? it shall brandishing shine, and who will not fear it? it shall thunder, and who will not shake with dread? God will threaten all, and who will not be terrified? before his face the earth doth tremble, and the foundations of the sea shake from the depths [6 Ezra 16:2-12]."
Gildas is drawing a comparison between the sinful Britons and the loss of their country (first to the Romans, then to the Saxons
) and the sinners in the Church, chastized by God.
A Chart of the Books, Their Names, and Where They Appear:
LXX Vulgate English
"The Greek Ezra" I Ezra III Esdras I Esdras
Canonical Ezra II Ezra* I Esdras Ezra
Canonical Nehemiah III Ezra** II Esdras Nehemiah
Apocalypse of Ezra — IV Esdras II Esdras
Bergren, Theodore A. Sixth Ezra : the text and origin New York: Oxford University Press, 1998.
Gildas. "De Excidio Brittaniae et Conquestu" Six Old English Chronicles ed. and trans. J.A. Giles. London: H. G. Bohn, 1848.