If you call this a work of classic fantasy meaning it's like every other fantasy series with its magic and wizards and made-up worlds, you would be wrong. If you call this a work of classic fantasy meaning it's a great piece of work that set the foundation – like Lord of the Rings – for a lot of other series, you would be right.
A Wizard of Earthsea is the first book in the Earthsea series and as all fantasy series should, it begins with a young wizard, Ged, who knows nothing of magic and the ways of being a wizard, other than his innate ability promising him a career as a great wizard. First he lives with a wise mage, and learns much about the simple things in life and magic and that everything has a cost. He soon discovers this when he performs a dark spell from a book he shouldn't have touched. A deadly shadow is summoned and then banished by his teacher, but Ged knows he will be facing it again.
Ged then travels to the isle of Roke where he spends years becoming a master wizard. Upon his graduation, he faces the dark shadow once more but is unable to hold against it and flees in terror. As a renowned wizard now, he travels around the islands helping those less fortunate, battling dragons and other monsters. Then again he faces the shadow and barely survives, fleeing once more. He returns to his old master, unsure what to do. The wizened wizard tells him he must face the shadow and in turn face his greatest fear. And so Ged heads out into the deep sea where none have gone before and there faces the shadow and wages a great battle, finally defeating him. The book ends with Ged returning to land with his friend, now a true and accomplished wizard with the thousands of islands of Earthsea before him.
What makes LeGuin's fantasy series more meaningful than most is that all the magic performed here comes at a cost, which the main character has to deal with throughout the book. It requires time and energy, afterwards one is tired; to create illusions is much easier than to actually change or create matter. Unlike the world of Harry Potter, here there are rules; not everyone can be a wizard. Along with this is the magical world of Earthsea with the many many islands of different peoples, a lot of which know little of each other. And for a wizard to travel from one island to another is a great adventure. The next book in the series is The Tombs of Atuan.