From the author's Introduction:

Pentecost is about purity, and then power. The event recorded in Acts 2 still, through the Holy Spirit, sanctifies and galvanises the Christian Church. That is the main thrust of this seventh collection of short Talks, which is offered to readers as a possible help for group study and discussion, and to preachers as a prompter of ideas and themes. Perhaps some readers will prefer to use the material as an aid for private reflection. I have arranged the Talks so that the key Bible passages follow the sequencing of the books of the New Testament. Some degree of overlap in the themes is to be expected.

Author Shaw Clifton adds: Today the Church needs articulate, intelligent, well-read preachers. The power
of preaching to a congregation remains undiminished. Where are today's Peters, or Martin Luthers, or John Wesleys, or Billy Grahams? If you are called to preach, then preach you must, however inadequate or unqualified you feel. God will open doors for you and equip you if you are ready to obey.