Here is a summary from Wikipedia:
Institutes of the Christian Religion is John Calvin’s seminal work on Protestant systematic theology. Highly influential in the Western world and still widely read by theological students today, it was published in Latin in 1536 and in his native French in 1541, with the definitive editions appearing in 1559 (Latin) and in 1560 (French).
The book was written as an introductory textbook on the Protestant faith for those with some learning already and covered a broad range of theological topics from the doctrines of church and sacraments to justification by faith alone and Christian liberty, and it vigorously attacked the teachings of those Calvin considered unorthodox, particularly Roman Catholicism to which Calvin says he had been “strongly devoted” before his conversion to Protestantism. The over-arching theme of the book – and Calvin’s greatest theological legacy – is the idea of God’s total sovereignty, particularly in salvation and election.
The Institutes are a primary reference for the system of doctrine adopted by the Reformed churches, usually called Calvinism.
Book One of the Institutes treats of the knowledge of God, considered as the Creator, Preserver, and Governor of the world, and of every thing contained in it.
This is an important work, and it has always been my desire to read it in its entirety, but I will take it one book at a time.
Calvin was definitely an "intuitive thinking" personality type. Authors like that often make my head hurt. The book is pretty heady, and I didn't find it had quite as much "heart" as Pascal's Pensées. It does amaze me that Calvin wrote this when he was in his late 20's! Would the church today take the writings of a 20's something so seriously?
This is a work of systematic theology, and systematic theology is not my thing (even though I studied it in seminary). I believe we could get so much more just reading the Bible over and over again. Thus why I lead a three year reading through the entire Bible (www.3yearbiblebookclub.blogspot.com).
My favorite part of this particular book were his thoughts on Satan. I do believe that Calvin understood the reality of the battle with the enemy of our souls.
I am taking a break before diving into Book 2!
By the way, the librivox.org recording by various narrators is very sound. Some are a bit monotone, but it makes it so much easier to get through this huge TOME, and it is FREE!