Greg Ganssle has produced the most fun and readable introduction to philosophy of religion I have ever encountered. His target audience runs from high school seniors to introductory college students, and I can say that I have enjoyed teaching an introductory philosophy course using this book. He presents the issues in a clear-headed way while drawing readers in with fun examples and humor.
After arguing for the value of thinking through philosophical questions in a reasonable way, Ganssle argues for open-mindedness in the sense of not being so sure of your views that you are not open to reason, but he also dismisses the idea that we must be neutral or that we must not make exclusive truth claims. Open-mindedness does not require having no views in those ways. I especially like seeing this in a book designed for younger students unfamiliar enough with philosophy to need some kind of way of heading off the simplistic kind of relativism that many students of philosophy find themselves stumbling over.
The main body of the work considers philosophical arguments for and against the existence of God. His presentation of the cosmological argument is the clearest I have ever seen, avoiding technical terminology when it is not needed but making the concepts as clear as can be done without such terms. His treatment of the design argument focuses on the fine-tuning argument after showing why very few are today convinced of biological design arguments, a choice perhaps reflecting a desire to stay out of intelligent design controversies in the political realm but nonetheless reflecting the philosophical consensus among believing philosophers today. His moral argument discussion helpfully begins by showing the difficulties in naturalistic accounts of morality, thus showing reasons why someone would turn to God as an explanation. I wish he had treated some naturalistic accounts of morality that are not relativist or eliminativist, and I really wished for a discussion of Euthyphro objections, but I do think his treatment of this argument is among the best I have read at this level.