Unlike many other religions, Judaism does not focus much on abstract cosmological concepts. There is substantial room for personal opinion on all of these matters, because as I said before, Judaism is more concerned about actions than beliefs. The scriptures also specify the mutual obligations created by these relationships, although various movements of Judaism disagree about the nature of these obligations. For more on these distinctions, see Movements of Judaism . As I said above, Judaism focuses more on actions than on beliefs, and books about Judaism tend to do the same.
Most books emphasize holidays, practices and observances.
The best summary of Jewish beliefs I've seen is Milton Steinberg's Basic Judaism . This book presents and contrasts the traditional and modern perspectives, and shows that we have more in common than many of us realize.