Eusebius of Caesarea.

One of the Christian historians.

Attributed text(s).
History of the Church.
Life of Pamphilus.
On the Martyrs of Palestine.
A collection of ancient martyrdoms.
Life of Constantine.
Against Hierocles.
Against Porphyry.
Against Marcellus, Bishop of Ancyra.
On the Theology of the Church.
On the Paschal Festival.
Treatise against the Manichaeans (?).
Demonstration of the Gospel (demonstratio evangelica).
Preparation of the Gospel (praeparatio evangelica).
Demonstratio ecclesiastica.
Praeparatio ecclesiastica.
Two books of objection and defense.
On the Numerous Progeny of the Ancients.
Interpretation of the ethnological terms in the Hebrew scriptures.
Chronography of ancient Judaea with the inheritances of the ten tribes.
Plan of Jerusalem and the temple.
On the names of places in the holy scriptures (Onomasticon).
On the nomenclature of the book of the prophets.
Commentary on the psalms.
Commentary on Isaiah.
Commentary on Luke.
Commentary on 1 Corinthians.
Commentary on Hebrews.
Other commentaries on scripture.
Elementary introduction (prophetical extracts).
Epistle to Carpianus (on the gospel canons).
Epistles to Stephen and Marinus.
Epistle to Alexander of Alexandria.
Epistle to Euphrasion.
Epistle to the empress Constantia.
Epistle to the church of Caesarea after the council of Nicaea.
Gospel canons (Eusebian canons).
Apology for Origen (with Pamphilus).
Oration at the dedication of the church in Tyre.
Oration at the Vicennalia of Constantine.
Oration on the sepulcher of the savior.
Oration in praise of the martrys (encomium on the martyrs).
Oration on the failure of rain.

Available text(s).
Skeptik (Greek text of History of the Church in .pdf).
Tertullian Project: Various works (English only).
New Advent: Church History (English only).
On site: iFrame text and translation of History of the Church (Greek and English).
Eusebius on the Four Gospels and Evangelists.
History (Greek only).
Parts of the History (Greek only).
Hodoi Elektronikai: Preparation, books 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 (Greek only).
Internet Archive: Preparation, books 1-10, 11-15 (Dindorf). Preparation, books 1-9, 10-15, notes (Gifford).
Hodoi Elektronikai: Demonstration, book 1.
Internet Archive: Demonstration, books 1-10 (Dindorf). Demonstration, books 1-5, 6-10. (Many thanks to Norman McIlwain for an amazing piece of detective work in tracking down these volumes.)

Related text(s).

Useful links.
Eusebius at EarlyChurch.
Eusebius in the Catholic Encyclopedia.

Eusebius was a Christian historian and bishop of Caesarea who flourished early in century III. His literary works are invaluable to the study of the Christianity of the first three centuries.

Photius of Constantinople summarizes a few Eusebian works in his Bibliotheca. Chapters 9-13, 27, 39, 118, and 127 all describe books by Eusebius, and chapter 89 deals with the continuation of the Church History by Gelasius of Caesarea.

Jerome, On Famous Men 81:

Eusebius, Caesareae Palaestinae episcopus in scripturis divinis studiosissimus, et bibliothecae divinae, cum Pamphilo martyre, diligentissimus pervestigator, edidit infinita volumina. de quibus haec sunt: ευαγγελικης αποδειξεως libri viginti, ευαγγελικης προπαρασκευης libri quindecim, θεοφανειας libri quinque, ecclesiasticae historiae libri decem, chronicorum canonum omnimoda historia, et eorum επιτομη, et de evangeliorum diaphonia, in Isaiam libri decem, et contra Porphyrium, qui eodem tempore scribebat in Sicilia, ut quidam putant, libri triginta, de quibus ad me viginti tantum pervenerunt; τοπικων liber unus, απολογιας pro Origene libri sex, de vita Pamphili libri tres, de martyribus alia opuscula, et in centum quinquaginta psalmos eruditissimi commentarii, et multa alia. floruit maxime sub Constantino imperatore et Constantio, et ob amicitiam Pamphili martyris, ab eo cognomentum sortitus est.

Eusebius bishop of Caesarea in Palestine was diligent in the study of divine scriptures and with Pamphilus the martyr a most diligent investigator of the divine library. He published a great number of volumes among which are the following: Demonstration of the gospel in twenty books, preparation for the gospel in fifteen books, theophany in five books, church history in ten books, chronicle of universal history and an epitome of this last; also On discrepancies between the gospels, on Isaiah in ten books, also against Porphyry, who was writing at that same time in Sicily, as some think, in twenty-five books, also one book of topics, six books of apology for Origen, three books on the life of Pamphilus, other brief works On the martyrs, exceedingly learned commentaries on one hundred and fifty psalms, and many others. He flourished chiefly in the reigns of Constantine the Great and Constantius. His surname Pamphilus arose from his friendship for Pamphilus the martyr.