This is really one book in two versions. The Easy Reader works for the low intermediate level, with short sentences, simple vocabulary, and generally easy exercises. The other, the high intermediate to advanced text, details events more finely and offers a greater range of vocabulary and more challenging exercises. The songs in both versions are the same, the illustrations and maps are identical. The only difference between them is the reading level. The advantage of having both these versions in mixed level classes is obvious. All students will be reading essentially the same story, at their comfortable level, and they will all sing the same songs together.