Cosmos by Carl Sagan. A little dated, but a classic. Sagan’s enthusiasm for his subject is inspirational.

Braiding Sweetgrass by Robin Wall Kimmerer. Part memoir, part reflections on how to repair humanity’s relationship with the natural world. The author is a botanist and a Potawatomi, and brings both perspectives to her work.

The Anthropocene Reviewed: Essays on a Human-Centered Planet by John Green. Thoughtful, heartfelt observations of humanity and its effects on the planet and the other beings that live on it, from a kind, decent, engaged, and nevertheless hopeful person.

The Soul of an Octopus: A Surprising Exploration Into the Wonder of Consciousness by Sy Montgomery. Really more personal reflections on octopuses the author has known and loved than an objective look at consciousness, but the tales are very moving.