This wonderful epic poem is the core work in the Tolkien corpus. It may be read in it's entirety in "The Lays of Beleriand" available in Hard or Paperback at any bookshop. Why the core work? On the headstone of the Tolkien grave at Wolvercote are two words from his whole life's work: "Beren & Lúthien".
A king there was in days of old:
ere Men yet walked upon the mould
his power was reared in cavern's shade,
his hand was over glen and glade.
His shields were shining as the moon,
his lances keen of steel were hewn,
of silver grey his crown was wrought,
the starlight in his banners caught;
and silver thrilled his trumpets long
beneath the stars in challenge strong;
enchantment did his realm enfold,
where might and glory, wealth untold,
he wielded from his ivory throne
in many-pillared halls of stone.
There beryl, pearl, and opal pale,
and metal wrought like fishes' mail,
buckler and corslet, axe and sword,
and gleaming spears were laid in hoard —
all these he had and loved them less
than a maiden once in Elfinesse;
for fairer than are born to Men
a daughter had he, Lúthien.
The first 22 lines (of 4,223) of The Geste of Beren and Lúthien
by J.R.R. Tolkien