- The development of Nathaniel's character over the course of the trilogy. I found Nathaniel's growth from child to young adult to be extremely realistic and inspiring. He moves from ambitious child (The Amulet of Samarkand) to teenage twit (The Golem's Eye) to learning and finally understanding what it means to be a good and even noble young man (Ptolemy's Gate).
- Stroud's extremely democratic, even revolutionary approach to a rigid class system. In Stroud's world, the magicians have power more because of birth than from talent. But this world is ending, and the end is near. That being said, revolution for its own sake is also criticized. Only revolution in the name of the people (as represented by Kitty's struggle) is justified; revolution for personal gain or to simply harm the opposition is also negatively portrayed.
- Stroud is a master of plot. All the loose threads are tied up, the cosmology explained, every action justified. And, even though the ending is slightly ambiguous in terms of what will become of some of the characters, it makes sense.
- Bartimaeus. What a wonderful, intelligent, urbane, fantastic character, even if he is a Djinni. His love and respect for his human "masters" is unbearably touching, made even the more so because they've earned the love and respect of this magnificent, omniscient creature.
I think The Bartimaeus Trilogy will stay with me for a very long time. I already miss Bartimaeus himself.