William Stace is the author of The GIANTS of Genesis 6: 

After more than twenty years of study and research, I began the long journey of writing The GIANTS of Genesis 6. My goal was to create a brief but in depth study that would give readers a foundational understanding of this mysterious and often misunderstood passage in Genesis. If you want to know the truth about what the Bible actually says about the Watchers, the Nephilim (Giants), and what happened long ago before the flood. This book is for you! You will never read the Bible the same way again...