Most scholars believe that transitions to democracy require the emergence of a broadly trusting public. But how trust works has remained mystifying. Tilly, a famed sociologist, offers a sweeping account of the connections between trust, social networks, and the rise and fall of democracy. His argument is that democracy is made possible not by general social attitudes of tolerance and trust but by the workings of "trust networks" -- religious sects, trade diasporas, craft associations, patron-client ties, credit networks, kinship groups, mutual aid societies, and many others -- that become indispensable for state rule. He argues that these trust networks have flourished inside and outside of political regimes over thousands of years, providing benefits and protections for their members while enforcing standards of conduct. Much of the book explores the logic and variation of social networks as they evolved in early modern Europe and have spread into the contemporary world. Tilly's claim is that democratic breakthroughs occur -- for example, in Mexico -- when trust networks are integrated into public politics through broadened participation and binding consultations between the state and those networks; state rules gain the support of social networks, while the networks acquire a stake in responsible government. In short, Tilly argues, the future of democracy will be written inside societies.