If Próspera were a normal town, Jorge Colindres, a freshly cologned and shaven lawyer, would be considered its mayor. His title here is “technical secretary.” Looking out over a clearing in the trees in February, he pointed to the small office complex where he works collecting taxes and managing public finances for the city’s 2,000 or so physical residents and e-residents, many of whom have paid a fee for the option of living in Próspera, on the Honduran island of Roatán, or remotely incorporating a business there. Nearby is a manufacturing plant that is slated to build modular houses along the coast. About a mile in the other direction are some of the city’s businesses: a Bitcoin cafe and education center, a genetics clinic, a scuba shop. A delivery service for food and medical supplies will deploy its drones from this rooftop. Próspera was built in a semiautonomous jurisdiction known as a ZEDE (a Spanish acronym for Zone for Employment and Economic Development). It is a private...