Book excerpt: Pluto looms large in Flagstaff, where residents and businesses alike take pride in their community's most enduring claim to fame: Clyde Tombaugh's 1930 discovery of Pluto at Lowell Observatory. Percival Lowell began searching for his theoretical "Planet X" in 1905, and Tombaugh's "eureka!" experience brought worldwide attention to the city and observatory. Ever since, area scientists have played leading roles in virtually every major Pluto-related discovery, from unknown moons to the existence of an atmosphere and the innovations of the New Horizons spacecraft. Lowell historian Kevin Schindler and astronomer Will Grundy guide you through the story of Pluto from postulation to exploration.