Marcus puts his knowledge as a historian of illustrated books for children to excellent use here. We see the Earthrise image in color on the cover, and then again in black and white as a frontispiece. Next, we encounter two similar shots: one from the Apollo 11 mission, the other snapped by an unmanned lunar orbiter. Together, the three images announce that this is not just a book about one photo: Steppingstones will lead us to a larger story. As we look at additional space-related artifacts and their captions, the longer written narrative (in effect the audio tour) carries us along. Visual storytelling is a distinct feature of youth nonfiction — and a treat if the author, like Marcus, has an eye for images that will spark interest and keep readers turning the pages.

The tale begins in 1957, with the Soviets’ surprise launch into Earth’s orbit of the first human-built satellite, Sputnik 1, sporting antennas that resemble “cat’s whiskers.” We experience Americans’ fear as the Soviets continue to be one step ahead of us, sending a dog, then a man, then a woman into orbit, and unmanned spacecraft to the moon.

President John F. Kennedy’s 1961 assertion that the United States should commit itself, “before this decade is out,” to “landing a man on the moon and returning him safely to the Earth” sets a deadline. NASA and its engineers press the limits of technology and skill to accomplish the mission, and are met with danger, failures and tragedy along the way.

Marcus’s smooth prose takes us quickly through the Mercury, Gemini and Apollo missions. A schematic depicts the internal construction of the massive Saturn V rocket, with the first engine powerful enough to hurl astronauts to the moon. There is plenty of human interest as well. We get to know Anders, Frank Borman and James Lovell — the crew of Apollo 8 — as individuals, from boyhood on.

Marcus tracks how the American space program intersected with the social and cultural crosscurrents of the ’60s. He mentions, in a note, the “Mercury 13” — a baker’s dozen of highly capable women who successfully completed a training program and were found to be “as well suited as the men NASA was selecting to crew its space missions, if not more so,” but were not chosen to fly — and cites, through the Rev. Dr. Martin Luther King Jr., questions that were raised about the value of the space program amid urgent human needs on Earth.