At only 112 pages of normal paperback format, God,Freedom, and Evil is a small book, but still fairly heavy reading. This was my first Plantinga book, but it appears to be a condensing and refocusing of some of his larger works as he points readers in search of fuller explanation to these other works in various footnotes. In that regard, this seemed like a good intro to his works, and a guidepost to future research. Plantinga's goal here is to look at the the "rational acceptability of theistic belief", not attempting to provide a "proof" for God, but rather answering the question, "Is belief in God a reasonable option?" He then divides the book into 2 main parts: "natural atheology" and "natural theology". In the first half on natural atheology, he addresses the so-called "Problem of Evil", while Part 2 addresses - very briefly - Aquinas' cosmological argument and Paley's teleological argument, followed by a more in-depth look at Anselm's ontological argument. Plantinga's style is an interesting mix of rigorous technicality in a conversational tone. Hence, the section on the problem of evil is reminiscent of a Socratic dialogue in its development/objection/refinement/objection cycle. Plantinga uses numbered premises as a shorthand throughout the book, so the reader should be prepared to jump back and forth a little to see which premises he is referencing when he says something like "[14] [15] & [18] necessarily entail [21], which is a self-contradiction. Therefore, this line of reasoning fails. But let's try changing premise [14] to say...." And so he goes through each argument showing why one version fails, then modifying premises to seek out a version that is not logically fallacious while still making its original point. In the end, the problem of evil argument for atheism does not survive Plantinga's analysis. The skeptic may be tempted at this point to say that Plantinga is biased and selective in his analysis, but what I think may surprise many skeptics is the rigor with which Plantinga treats the problem of evil. He takes this objection to God seriously, and goes through it with great thoroughness. This is not the typical shallow throwing about of the issue you might see on the internet, but a very methodical academic examination of it, with a modest conclusion, namely, that "the Free Will Defense, however, shows that the existence of God is compatible, both logically and probabilistically, with the existence of evil; thus it solves the main philosophical problem of evil."
The skeptic might also be surprised that he did not seem to have any qualms about critiquing theistic arguments, as he pointed out flaws in all three classical cosmological, teleological, and ontological arguments. What did disappoint me a little was his brevity on the cosmological and teleological arguments. He criticizes all 3, but stops at the critique of the first 2. He does say in the introduction that he will be focusing on the problem of evil on the atheist side, and the ontological argument on the theist side, but his treatment of the cosmological and teleological arguments may leave the reader with the impression that these are not robust arguments. To spend 8 pages on these 2 lines of reasoning, without answering the objections to them, and then conclude that they are both "unsuccessful" is an unfortunate move on Plantinga's part. That said, his treatment of the ontological argument is actually why I bought this book.
Although a Christian myself, I'd never found Anselm's version of the ontological argument for God very compelling. But William Lane Craig had referenced Plantinga's reformulation of it in his "Reasonable Faith" book, and that really forced me to rethink my hesitancy with this line of reasoning. Published in 1974, Plantinga's treatment of it here is not as polished as it is in later statements of it, but it's nice to see him really walk through the development here. He starts with Anselm's version, looks at objections and addresses them if they seem to misunderstand the actual argument, or adjusts the premises to answer objections. Plantinga's biggest contribution here is probably bringing his "possible worlds" frame of reference that he uses in answering the problem of evil to bear in fortifying the ontological argument. The ontological argument has always been pretty abstract stuff, so this frame of reference is very helpful, in my opinion, and does improve the argument dramatically. Even so, in the end, Plantinga is respectfully modest in his survey of the argument in his end form of it, as he states, "What I claim for this argument, therefore, is that it establishes, not the truth of theism, but it's rational acceptability." And in Plantinga's formulation, the ontological argument does that surprisingly well given the ridicule it has taken over the centuries. He would say, I think, that this is not a case-closer, but a door-opener, in that it removes claims of intellectual objections with which atheists may have tried to "barricade the door" against God, and reveals them to be simply willful rejection rather than carefully reasoned objections as they claim.