What is the theme in The Adventures of Ibn Battuta, a Muslim Traveler of the Fourteenth Century by Ross E. Dunn?

Dar al -Islam and its growth is at heart of this book. The "Dar al-Islam," or "Abode of Islam" as Dunn interprets it in the introduction to The Adventures of Ibn Battuta, refers to the overall region of the world where Islamic law is the official law of the land. Within the Dar al-Islam are numerous independent areas which sometimes war with one another, but they all still fall under the umbrella of the larger concept of an Islamic world.