Hildafolk by Luke Pearson is the first of the Hildafolk series and was done to highlight Pearson's artwork. It's about a third the length of the later Hilda books but shows the potential of the following ones.
Hilda lives with her mother in a cabin in the foothills. She adores nature and the creatures who live there: mundane and magical. She's wary of giants. She isn't as brave about the magical elements of her surrounds as she will be. But she's willing to believe and willing to share.
She loves to explore. She's prone to get lost. The forest is changeable. In the later books, Hilda's ties to the spirit world are firmly established. She can see them because she thinks like them, and she takes things at face value. Here, he shows this through her crossing paths with a giant. She's lost and she believes he knows where he's going. Turns out, he doesn't.
Though it's short and not as refined as the later ones, it's still a must read for fans of Hilda.