I read Introducing Plato last night. I picked it up at Half Price Books because Plato is referenced repeatedly in Objectivism: The Philosophy of Ayn Rand. "Introducing Plato" covers many of the ancient Greek philosophers of the period and shows how they influenced or were influenced by Plato. It covers his life, his philosophy, and his influence through the ages.
By reading "Introducing Plato", I now have a far better understanding of Objectivist philosophy. Before I read this book, I found some of Rand's terminology a bit odd but now I realize that she was engaged in a conversation with the ancient philosophers that I had walked in on toward the end. I also see where she agrees and where she deviates with them on the important questions. I would recommend "Introducing Plato" to any student of Objectivism that has not previously studied the ancients.
Ayn Rand was no fan of Plato. She prefers to praise Aristotle, his student of twenty years. I see that a second edition of Introducing Aristotle in coming out in August. I am looking forward to it.