The latter portion of this book, "A Treatise on Peace of Soul," was recommended to me by my spiritual director.
I found the first portion, "The Spiritual Combat," to be a little dry in some parts, and the prayers a little too flowery. I prefer The Imitation of Christ instead.
The second portion on interior peace is excellent - specific, direct, and gentle. Whoever wrote it had the heart of a spiritual father and it has greatly helped me during a time of spiritual anxiety / worry. Highly recommended.