Guadeloupe’s de facto capital is located near the narrow isthmus connecting the butterfly-shaped island’s two wings. Grand Terre is the larger wing, fringed with the sort of beaches that bring visitors to the Caribbean. The museum of Saint-John Perse is housed in an intact colonial-era mansion, and is dedicated to the Nobel Laureate Alexis Léger, whose nom de plume was St-John Perse. The house is…