The Two Babylons - Alexander Hislop

or, The Papal Worship Proved to be the Worship of Nimrod and His Wife.

This book is quoted and used as a resource by many writers and truly became a reference work. Although it is meticulously researched it is a controversial book and many of the statements in it have lately been questioned. It is not intended to be used to beat someone else over the head with. However it does a great job of showing us how the Church (mostly Medieval Catholic church) adopted and tried to Christianize pagan symbols and practices. In this it can help to equip us not to fall into pagan practices. This scholarly classic, was first published as a pamphlet (1853) and republished and expanded as a book (1858)