And of course, this fantasy, written in 1924, was a seminal influence for many, many great authors: Tolkein, Beagle, Lovecraft, Leiber... that list goes on and on. For god's sakes, Neil Gaiman just about lifted the entire story line for Stardust from here, though it did not keep him from writing the introduction for this book.
The King of Elfland's Daughter is about a mortal man taking an elfin princess from elfland as his bride, losing her, and finding her again. It is beautiful, imaginative beyond compare, and is written in a cadence that sounds like it should be sung in an opera. There are hunted unicorns, lands that move like sea tides, ancient runes, witches and trolls, and stars so glorious they must be worshiped. The comparisons between the land of men, which always changes and the immutable elfland, were also sonorous to read: He saw through cracks in old shutters the stars go moving by; he saw them pale: he saw the other light spread; he saw the wonder of sunrise; he felt the gloom of the loft all full of the coo of the pigeons; he watched their restless ways: he heard wild birds stir in near elms, and men abroad in the morning, and horses and carts and cows; and everything changing as the morning grew. A land of change!
Don't read about Lord Dunsany. Just don't.