H. A. A. Kennedy 
Vital Forces of the Early Churches [PDF ebook] 

’No more fitting summary of the account given in Acts of the Early Christian movement could be found than the words of chap. xix. 20: ’So mightily did the message of the Lord grow and prevail.’ The book intends to be a narrative of the victorious progress of the good news of Christ. Even those elements in it which fail to appeal to us were influential at the close of the first century A.D. This was what Christianity had achieved. It had come to occupy successfully the chief centers of the ancient world. It had spread from Jerusalem to Rome.’ — From Chapter 1