[1] His father, Reverend Frank Kroll, attended Practical Bible Training School (as it was then called) from 1936 to 1939 and pastored the Park Gate Baptist Church in Ellwood City for thirty-three years.

Begun in 1939 by Theodore Epp on radio station KFOR (AM) in Lincoln, Nebraska, the Back to the Bible broadcast became a worldwide ministry by the time its founder retired in 1981.

Epp was succeeded by Warren W. Wiersbe, former pastor of Moody Church in Chicago, Illinois, who served as leader of the Lincoln, Nebraska-based ministry between 1981–1989.

At the time of his retirement, Woodrow Kroll was heard daily on 1250 radio stations in the United States and anywhere in the world the English language was spoken.

In 199 sessions, each 20-22 minutes long, Kroll uses a conversational style as if he were sitting across an imaginary table to guide the listener into knowing what Christians believe and why they believe it.

Using either a USB, an app, print, or a solar-powered handheld device, The HELIOS Projects are designed to put A Bible and Christian faith education right in your hand.