The author's identity is unknown. The Bibliotheca circulated under the name of Apollodorus, and the 9th-century patriarch Photius read the work as the product of Apollodorus the Grammarian. That identification pointed to Apollodorus of Athens, a Hellenistic scholar born around 180 BCE, trained under Aristarchus of Samothrace and active in Alexandria before moving through Pergamum and returning to Athens. Apollodorus of Athens wrote poetry, chronology, Homeric commentary, grammar and a twenty-four-book treatise On the Gods. His name carried enormous authority in ancient scholarship, which helps explain why the later mythographic handbook was attached to him.

The attribution cannot be accepted. Apollodorus of Athens died after 120 BCE, while the language, style and historical horizon of the Bibliotheca fit the 1st or 2nd century CE. The mythographer uses a different prose manner, cites sources in a form unlike Apollodorus of Athens and never displays the chronological precision that made the Athenian scholar famous. The work therefore belongs to the Roman imperial period. Its author's city, education, profession and life remain unknown.

The title is also uncertain. Bibliotheca means Library and suggests a storehouse of stories, but the manuscripts do not preserve a stable authorial title. Some ancient references suggest that Genealogia, Genealogies, may describe the work more accurately. The conventional division into three books is editorial rather than necessarily authorial. Modern editions and translations still use Bibliotheca or The Library because those titles have become inseparable from the work.

The Bibliotheca is one work, not a collection of separate compositions by different known authors. Its companion text, the so-called Epitome, does not represent a second authentic work by Pseudo-Apollodorus. The Epitome is a modern editorial name for one or more summaries of the Library and related material, preserved in later manuscripts. Sir James George Frazer's Loeb edition famously conflated two summary traditions to reconstruct the lost ending of the main work. Modern research treats the relationship among the full text, the summaries and later excerpts as a complicated problem of transmission rather than a simple case of an original work plus an ancient abridgement.

Book One begins with the beginning of the gods. It opens with Chaos, Earth, Tartarus and Eros, then presents Sky as Earth's first partner and traces the birth of the Titans, Cyclopes and Hundred-Handers. It narrates the castration of Sky, the punishment of the Titans, the rise of Zeus and the Titanomachy. It continues with the wars against the Giants and Typhon, then turns to the Olympian generation and the birth stories of Zeus's children. Demeter's search for Persephone, Apollo and Artemis, Hermes, Dionysus, Heracles' divine ancestry and the major monsters are compactly summarised.

The first book then moves from divine genealogy to the families of Deucalion and Aeolus. Deucalion and Pyrrha survive the flood and become ancestors of the Greek people through Hellen. Hellen's sons Dorus, Xuthus and Aeolus distribute the land and give their names to the Dorians, Ionians and Aeolians. From Aeolus come Sisyphus, Athamas, Salmoneus, Cretheus, Canace, Alcyone, Calyce and the other figures who carry the mythic history of Thessaly, Corinth, Boeotia and the islands. The book also treats the house of Oeneus, the hunt of the Calydonian Boar, the story of Meleager, Melampus, Admetus, Pelias and the voyage of the Argonauts.

Book Two turns to the family of Inachus in the Argolid and the heroic house of Perseus. It begins with Io's wanderings, the Danaids, Proetus and the Proetides, and Bellerophon's combat with the Chimera. It then presents Danae and the birth of Perseus, Perseus' slaying of Medusa and rescue of Andromeda and the complex genealogies that join Perseus, Electryon, Amphitryon and Alcmene. From these lines emerges Heracles.

The central portion of Book Two is the Heracles cycle. Pseudo-Apollodorus narrates the hero's birth, his exposure, his first feat against the snakes, the madness sent by Hera, the servitude to Eurystheus and all twelve labours. He continues through Heracles' wars, marriages, accidental killings, madness and death on Oeta. The book then treats the return of the Heraclids, the generations after Heracles and the settlement of Argos, Lacedaemon and Messene. It is one of the fullest ancient prose syntheses of the Heracles tradition.

Book Three begins with the family of Agenor and moves through Europa, Cadmus, Minos, Pasiphae, the Minotaur, Ariadne and the Cretan royal house. It recounts Catreus, Glaucus and Polyidus, then follows Cadmus to Thebes and treats Semele, Actaeon, Dionysus, Antiope, Amphion and Zethus. The Oedipus story follows, then the Seven against Thebes, the Epigoni and the final destruction of the Theban royal house. The book turns to Lycaon, Callisto, Auge, Atalanta, the Pleiades, Hermes, Asclepius, Coronis, Leda, the Dioscuri, Dardanus, Priam, Aeacus, Telamon, Peleus and Thetis.

The third book ends with the Athenian cycle and Theseus. It treats Cecrops, Erichthonius, Orithyia, Aegeus, Medea's arrival at Athens, Theseus' birth and youthful feats, the Minotaur, Ariadne, the Amazons, Pirithous, Helen's abduction and Theseus' descent to the Underworld. The full text then breaks off during Theseus' return journey. Photius had read the missing conclusion and reports that the original work continued into the Trojan War and the homecomings of the Greek heroes. The Epitome and related summaries preserve the broad contents of that lost portion.

The lost section covered the courtship and abduction of Helen, the gathering of the Greek fleet, the sacrifice of Iphigenia and the first years of the Trojan War. It continued with Achilles, Ajax, Palamedes, Philoctetes and the deaths of major heroes. It included the fall of Troy, the returns of Agamemnon, Menelaus, Odysseus and the other Greeks, and ended with the death of Odysseus. Because the main manuscript ends before this material, the Epitome's account remains indispensable but cannot be treated as a verbatim continuation of Pseudo-Apollodorus's own prose.

The Bibliotheca's method is genealogical. A family is introduced, its ancestors and descendants are named, and the major myths attached to its members are summarised in chronological order. A hero's marriage leads to his children; a child's city leads to the next local cycle; a divine parent introduces a new heroic line. The device allows the compiler to move across Greece without losing structure. Boeotia, Thessaly, Argos, Laconia, Messene, Crete, Athens, Phoenicia, Egypt and Troy all become stations on a family tree.

The compiler preserves variants with unusual clarity. He frequently names Homer, Hesiod, Pherecydes, Acusilaus, Hellanicus, Pindar, Aeschylus, Sophocles, Euripides and later writers. A passage may give one version in the main narrative, then add another with a phrase such as some say, followed by an author's name. The technique makes the Bibliotheca invaluable for reconstructing lost poems and local traditions. It also means the work is not a single seamless myth. Different sections reflect different sources, priorities and levels of detail.

The directness of those sources remains debated. Some passages appear to follow early epic and mythography closely, preserving details that would be difficult to explain through a late intermediary. Others contain material that must have passed through Hellenistic handbooks, tragic summaries or already contaminated mythographic traditions. The old image of Pseudo-Apollodorus as a careless epitomator who never opened the original poems has been replaced by a more nuanced view: he sometimes uses direct sources, sometimes intermediate handbooks and sometimes a mixture of both. The evidence varies by section.

His prose is plain, compressed and utilitarian. He does not attempt the drama of Homer, the grandeur of tragedy or the argumentative style of a philosopher. He gives the essential genealogy, the key events, the names of spouses, children and cities, and then moves forward. The brevity is a strength. In a few lines, he can preserve the outline of a myth whose fuller version survives only in a fragmentary papyrus or a late paraphrase. In a few names, he can connect a local hero to a Panhellenic genealogy.

The work also has limitations. Its genealogical order can distort the narrative emphasis of a myth. Its compression removes ambiguity and sometimes turns conflicting variants into a smoother account than any single ancient source offered. Its Roman date means that it is a late witness to myth, not an early authority. A modern reader who needs the earliest evidence should go behind Pseudo-Apollodorus to Homer, Hesiod, lyric poetry, tragedy, local historians or iconography. The Bibliotheca is a map of the tradition, not the territory itself.

The transmission of the text was exceptionally narrow. Photius read a complete copy in the 9th century, but the surviving medieval tradition descends from a single incomplete 14th-century manuscript, Parisinus graecus 2722, conventionally called R. That manuscript breaks off during Theseus' journey. Cardinal Bessarion's 15th-century copy became the ancestor of the other surviving manuscripts. The work survived only because Byzantine scholars continued to copy it as a useful handbook, and later Renaissance humanists recovered and printed it.

The first printed edition appeared at Rome in 1555 under the editorship of Benedetto Egio, who divided the work into three books. Hieronymus Commelinus produced an improved text at Heidelberg in 1559. Christian Gottlob Heyne established the first major modern edition through comparative manuscript work in the 1780s. Richard Wagner's Teubner edition of 1894 became the standard 19th-century text. Frazer's 1921 Loeb Classical Library edition and translation made the work accessible to English readers. Robin Hard's Oxford translation, Smith and Trzaskoma's Hackett edition and Manolis Papathomopoulos's Greek edition represent more recent milestones.

The Bibliotheca's influence begins with its Byzantine readers. John Tzetzes used it repeatedly in his commentaries and didactic poems. Later Byzantine scholars mined it for mythological names and genealogies. Renaissance mythographers, poets and painters used it to navigate the immense field of Greek story. It became a standard reference for understanding Ovid, Homer, Pindar and the tragedians. Early modern editions placed it beside Hyginus, the scholia and the Latin mythographers as a compact guide to the ancient world.

Its modern importance is even greater. The Bibliotheca preserves material from lost works of Hesiod, Pherecydes, Acusilaus, Hellanicus, the Epic Cycle and dozens of tragedies. It provides a framework for comparing local variants. Its genealogies reveal how Greek cities constructed ancestry and connected themselves to heroic families. It shows the Roman-period impulse to organise mythology into a coherent library of stories. Without it, the modern study of Greek myth would lose one of its most convenient and revealing maps.

Pseudo-Apollodorus also presents a warning. Because his handbook is readable, systematic and complete in appearance, it is easy to treat it as the default version of Greek myth. Readers then repeat its account without recognising that it may be one variant among many. The careful use of the Library requires citation of its sections, comparison with earlier sources and attention to the work's late date. Its greatest value lies in directing the reader toward the tradition, not in replacing the tradition.

The accurate account of his works is therefore simple. Pseudo-Apollodorus wrote the extant Bibliotheca. The so-called Epitome is a later summary tradition used to recover the lost ending, not a secure independent work by the same author. No other work can be assigned to Pseudo-Apollodorus. The Chronicle, On the Gods, the Homeric commentary and other learned writings belong to Apollodorus of Athens. Confusing the two figures would repeat the ancient mistake that the modern name Pseudo-Apollodorus was created to prevent.