Growing up on a Kansan farm gave Clyde W. Tombaugh plenty of sky to explore, plenty of time to learn all he could about astronomy. He and his father and uncle trained their homemade telescope on the planets. Clyde drew the surfaces of Mars and Jupiter and shared his drawings with Lowell Observatory in Flagstaff, Arizona. Gadzooks! They hired him to help search for a new planet! After 300 days of scouring the sky with a photographic telescope, Clyde pinpointed Pluto's location on February 18, 1930. With tenacity and a passion for astronomy, he found the last planet in the solar system. The scientific community and the public were jubilant. Clyde's story is perfect for STEM students. The back matter provides a follow-up to the status of Pluto, now considered a dwarf planet, and the 2015 New Horizons Pluto flyby. There is also a bibliography, glossary and biography of Tombaugh's life of discovery.