The Battle of Okinawa: The Last Epic Struggle of World War II by Gerald Astor. A detailed account of the 82-day battle that destroyed much of what is now Naha and killed roughly a quarter of the island's civilian population. Essential context for understanding why so much of what you see in the city is reconstructed.
Typhoon of Steel: The Battle for Okinawa by James and William Belote. A thoroughly researched narrative of the battle from both American and Japanese perspectives, with good detail on what the island looked like before and after the fighting.
The Island of Sea Women by Lisa See. A novel about haenyeo (free-diving women) set on Jeju Island in Korea, but recommended because it engages seriously with the same post-war Pacific world and the disruptions of occupation and modernization that shaped Okinawa in the same period. Not about Okinawa specifically, but illuminating.