It is unusual to see an informational book about time. It makes me think there should be a kids' book about ontology -- consciousness and existence, Heidegger with concrete examples. The examples of time in this book were straightforward, but after a while it became clear that it was just a book about how many of certain things can happen in a unit of time. That got old. Also, there was clear text about how time developed as a measurement concept, but nowhere were these measurement concepts (such as minutes or seconds) presented visually in a diagram. Interesting fact about when and where seconds, minutes were developed. That part of the text is easy to find on wikipedia, so it's great that most of the visuals and time in the book are spent on points of comparison.