I read a children's fantasy book in the 80's that had illustrations. It was about a boy and possibly a girl in a magical forest. There were harpies that menaced them. Does anyone know what book that was?
80's, boy, girl, forest, menacing harpies. Not much to go on, but could easily have been one of Piers Anthony's many Xanth novels which filled shelves in bookstores from the late 70's on. There was one in particular with a nasty harpy in it back in 84 or so, but it's been so long, and there are so many Xanth novels that I couldn't pin it down.
I think this might well be The Seventh Princess by Nick Sullivan. This is a short middle-grade story about a girl who is transported to a fantasy land, where she is called a princess. The six princesses before her have all been transformed into Harpies. First published by Scholastic in 1983.
I don't remember the story having a boy, but it does have a dwarf.
Is it Ronia The Robber's Daughter? That was a favorite of mine growing up.
Birk and Ronia run away to the woods, where they live in a cave and experience several harrowing adventures with the wood's indigenous wildlife, including trolls, forest gnomes, and harpies.
Sounds like it might be Tamora Pierce's The Immortals series. Set in the same world as her Alanna books.