I've recently started reading Tozer, and I noticed this title as I was in a Bible study going through First Peter.
This is not a commentary. My impression is that it was a collection of seventeen sermons, sixteen of which were from First Peter (the last touched on Jude). This still gives insights on certain issues through Peter's first Epistle.
This is not in the category of his classics "Pursuit of God" or "Knowledge of the Holy". However, this is a very useful and instructive book.
Have you read any Tozer books? Have you studied 1 Peter recently?