One of the top sights in Dublin and Ireland's finest national treasure is the Book of Kells, on display at the Trinity College Library. The Book of Kells is an illuminated manuscript in Latin, containing the four Gospels of the New Testament transcribed by Celtic monks in about 800AD, when the rest of Europe was in the midst of the Dark Ages. The manuscript takes its name from the Abbey of Kells, which was its home for centuries. It is widely regarded as a masterwork of Western calligraphy and represents the pinnacle of Insular illumination. The lettering is in iron-gall ink an the colors were made from a variety of substances, some of which were imported form distant lands.

In their extravagance and complexity, the illustrations and ornamentation of the Book of Kells surpass other arts produced in the British Isles during the time. The decoration includes both the traditional Christian iconography and the ornate swirling motifs typical of Insular art. Figures of humans, animals and mythical beasts, along with Celtic knots and interlacing patterns in vibrant colors, enliven the manuscript's pages. Many of these minor decorative elements are imbued with Christian symbolism and further emphasize the themes of the major illustrations.

The manuscript today has 340 folios and is bound in four volumes of high-quality calf vellum. The unprecedentedly elaborate ornamentation is vibrant with interlinear miniatures and marks the furthest extension of the anti-classical and energetic qualities of Insular art.