French writer and illustrator Isabelle Simler focuses her books on the natural world. This one is a gorgeous meditation on the color blue in the sky, animals, and plants. It is for ages 4 to 8 but we think all ages will enjoy it.

"The day ends. The night falls. And in between . . . there is the blue hour," Simler begins. We are then introduced to a wide variety of animals who are active at this time: a blue jay, a blue fox, blue poison dart frogs, blue-feathered songbirds, silver-blue sardines, a Russian blue cat, a blue whale, a blue-ringed octopus, and more. And then there are blue plants: forget-me-nots, bluebells, cornflowers, and violets.

In a clever design touch, the inside jacket spread identifies orbs of 32 different types of blue. We are reminded to pay attention to all the variations of each color. A fun exercise to do with children after enjoying the pictures in this book is to take another color and see how many examples of it you can find in nature.