I am rereading this set because I found it in a thrift store. I like them better than A Wrinkle in Time. I think they are a little more accessible. And I just found out the author Susan Cooper was a collaborator of Hume Croym and Jessica Tandy and married him some time after Tandy's death. She wrote some wonderful screen plays. The books have a lot of Welsh culture in them and are about children that are trusted to do hard difficult tasks with little rewards.