Assuming you're a Christian: Have you heard of Cyrus Scofield? More specifically, have you heard of the Scofield Reference Bible?
Stephen Sizer is a theologian and author with quite a lengthy biography and he joined me on my podcast to chat about the dangerous influence of Scofield (including who he was and who he worked with).
Basically, over a century ago, he spread the idea of biblical dispensationalism—a false doctrine—through a variation of the Bible called the Scofield Reference Bible. It was really just republications of standard Bible translations but with added footnotes on each page. Many Bibles today still use the Scofield footnotes, knowingly or unknowingly.
It's these footnotes that influenced tens of millions of Christians in the coming decades.
What's in these footnotes?