Complex sentence: It is the main source of his philosophical views, as opposed to his opinions on Jewish law, and since many of the philosophical concepts are relevant beyond strictly Jewish theology, it has been the work most commonly associated with Maimonides in the non-Jewish world.
Split into simpler sentences: It is the main source of his philosophical views, as opposed to his opinions on Jewish law. Furthermore, as many of the philosophical concepts are not restricted to Jewish theology, it has been the work most commonly associated with Maimonides in the non-Jewish world.