As a member of the integrated Women’s Army Corps, Private First Class Sarah Keys served her country as a receptionist at Fort Dix, New Jersey. When she boarded a bus home to North Carolina in 1952, she never expected to be arrested and charged with disorderly conduct for refusing to move to the rear so a white Marine could take her seat. Her landmark 1955 Civil Rights victory, “Sarah Keys v. Carolina Coach Company” not only desegregated interstate bus travel, it also provided the legal precedent needed during the 1961 Freedom Rides to pressure the Interstate Commerce Commission to properly enforce its Sarah Keys ruling. Often overlooked in many accounts of the Civil Rights era, her arrest and victory are crucial milestones in the fight against segregation. Riding into History draws on years of personal conversations with Sarah Keys Evans as well as extensive research to present a biography of this hero and her role in the struggle for civil rights alongside the long history of many other Black Americans, especially women, who protested racial segregation in interstate travel.

A celebration of the seemingly simple idea that allowed us to imagine the world in new dimensions—sparking both controversy and discovery. 
 
The stars of this book, vectors and tensors, are unlikely celebrities. If you ever took a physics course, the word “vector” might remind you of the mathematics needed to determine forces on an amusement park ride, a turbine, or a projectile. You might also remember that a vector is a quantity that has magnitude and (this is the key) direction. In fact, vectors are examples of tensors, which can represent even more data. It sounds simple enough—and yet, as award-winning science writer Robyn Arianrhod shows in this riveting story, the idea of a single symbol expressing more than one thing at once was millennia in the making. And without that idea, we wouldn’t have such a deep understanding of our world.

Vector and tensor calculus offers an elegant language for expressing the way things behave in space and time, and Arianrhod shows how this enabled physicists and mathematicians to think in a brand-new way. These include James Clerk Maxwell when he ushered in the wireless electromagnetic age; Einstein when he predicted the curving of space-time and the existence of gravitational waves; Paul Dirac, when he created quantum field theory; and Emmy Noether, when she connected mathematical symmetry and the conservation of energy. For it turned out that it’s not just physical quantities and dimensions that vectors and tensors can represent, but other dimensions and other kinds of information, too. This is why physicists and mathematicians can speak of four-dimensional space-time and other higher-dimensional “spaces,” and why you’re likely relying on vectors or tensors whenever you use digital applications such as search engines, GPS, or your mobile phone.

In exploring the evolution of vectors and tensors—and introducing the fascinating people who gave them to us—Arianrhod takes readers on an extraordinary, five-thousand-year journey through the human imagination. She shows the genius required to reimagine the world—and how a clever mathematical construct can dramatically change discovery’s direction.