"We are all time travelers journeying together into the future. But let us work together to make that future a place we want to visit. Scientist and educator Stephen Hawking spent his life trying to unravel the mysteries of the universe. But, he still had many questions—and he wanted every reader, every child, to come together to help answer them: How can we save the planet? How can we learn to be there for one another? Adapted from Professor...