I give this work a five, but it does have some problems. Fist, and Helyer admits this in the introduction, he does not use any of the non-canonical works on Peter in his discussion. Ok thats fair, but if your arn't going to use the non-canonical works of Peter then why do you continually site Enoch and his four books through out the work? This really bothers me as an author is not consistent in what sources he includes and what he holds out as references. Maybe I'm picky. Kudos to Helyer in discussing the non - canonical works by or on Peter. But he could have cited them and then also discussed in more depth why he and other historians, theologians, archeologists, writers, etc have not put these works in the cannon. I believe that as you learn catholic, as in church universal, history you find the answer in 325 CE in Nicaea.
The Council of Nicaea was called by Constantine to create one Church and one Creed. For in 306CE when Constantine I took over as Emperor he had to continually fight to hold the Empire together from both interior and exterior attacks. Many of these interior attacks came from the church that he made the Supreme Religion of the Empire. Constantine planned to use this newly legalized religion, Christianity, to unite the Empire behind one God and as Emperor he would, by the divine right of kings, be the head of that political entity and the Church would back his plans. All this can be read in Gibbons, Decline and Fall of the Roman Empire. In 325 Constantine called the Council of Nicaea. It met for four to six weeks and included all 1800 Bishops in the Empire. Well almost all, The Copts of Egypt and the Jacobines of Syria declined the Emperors invitation, also declining were the Churches in India and many of the ascetic monks of the Sinai, lower Egypt, Ethiopia, and the Yemen, History of Eastern Christianity, by Aziz S. Atyia. for further information on others who declined and their reasons. But I digress. Nicaea had a distinct political over tone. Constantine attended every session and chaired several himself. Many works that the people felt were Canonical were left out of the canon because they preached, to Constantine and the Bishops heresy. The acts of Thecala preached that all people once they become Christian also became born again virgins and to not defile their new found virginity with earth bound sex. Thecala was not the only book that preached this idea. In the Acts of Peter he also preaches new found virginity, an idea that takes hold on Romes elite wives and leads to Peter leaving Rome. There are also multiple letters from Paul preaching celibacy that were excluded at Nicaea from the canon. Also Peter preached in his Acts, the Book of Peter, several of his letters, The Preaching of Peter, and The Apocalypse of Peter, this is paraphrased, that one could find God as long as you could read the Gospels and the letters of the Apostles and then meditate on there meaning and God would come to you and explain the Word. Remember, this council is to build ONE catholic Church or to put it another way ONE IMPERIAL CHURCH with the Bishops beholding much of their power to the Emperor. SO a church that said by reading, prayer, meditation, maybe even fasting one could find God is not a Church structure that will support the throne. Obviously these works have to be lost to the "Official Canon". And after Nicaea, they were. However, the people still used them in their own churches towns, villages as supplements to the Canonical Bible. Thecala was not removed as a Saint until 1968 and Vatican One. The Petrine works were used in India until the Jesuits arrived with the Portuguese in the 1600's. The Gnostics still today use many of the non- canonical books in their service. See "Lost Scriptures: Books that DId Not Make It into the New Testament" by B. D. Ehrman.
With all this there is still a lot of good information in this work; for instance, Christ actually means King in Aramaic. The theology is extremely sound and the references will get you back into parts of the Bible that you may have forgotten or just never read, especially the Old Testament references. I would suggest that you have your Bible next to you to reread the Old Testament references and either before or after you read Peter you read the Ehrman work to get a more complete idea of what Peter did or may have said. Even Helyer admits that the "Acts of Peter' is quite possibly genuine or at least written by an eye witness.
Altogether a very readable, set up for a Sunday School Study Group in the SEC states, work with a boat load of great information.