Torrey in his clear and simple way deals with this important subject in the following way:
1. The baptism with the Holy Spirit: what it is and what it does
2. The necessity and possibility of the baptism with the Holy Spirit
3. How this experience can be obtained
4. Re-filling with the Holy Spirit
5. How spiritual power is lost
Torrey states further: "It was a great turning point in my ministry when after much thought and study and meditation I became satisfied that the baptism with the Holy Spirit was an experience for today and for me, and set myself to obtain it.
"While a great deal is said in these days concerning the baptism with the Holy Spirit, I am afraid that there are many who talk about it and pray for it who have no clear and definite idea if what it is. But the Bible, if carefully studies, will give us a view of this wondrous blessing that is perfectly clear and remarkably definite."
In this book, Torrey gives that clear and definite Biblical teaching. [via]