R.S. Thomas, Collected Poems — Thomas was vicar of Aberdaron from 1967 to 1978 and is buried in the churchyard at Llanfaelrhys. His late poetry was shaped by the elemental landscape of the peninsula — the sea, the headlands, the island on the horizon. The Bright Field, Pilgrimages, and the poems in H'm and Frequencies all draw directly on the Llŷn. Reading them before or during a visit changes how you see the place.
Jan Morris, Wales: Epic Views of a Small Country — Morris, who lived in Wales for most of her life, writes about the country with deep affection and occasional impatience. The chapter on the north and the Llŷn Peninsula captures both the beauty and the cultural intensity of the Welsh-speaking heartland. A useful primer before any visit to this part of Wales.
Emyr Humphreys, Outside the House of Baal — Humphreys is the great Welsh novelist of the 20th century, and this 1965 novel — set in rural north Wales over six decades — is his masterpiece. It is not set on the Llŷn specifically, but the cultural world it describes — Welsh Nonconformism, the tension between Welsh and English, the decline of a way of life — is precisely the world you encounter here. Difficult and rewarding.