The Holy Bible, King James Version (1611) by (you know) various authors.
I got the idea of reading the entirety of the KJV in 2011 when the book had it's 400th printing anniversary. It took me a few years to get around to actually getting and starting a copy, but I got it together early last year and started my journey. By chipping away at a few pages every day, I worked my way through both the Old and New Testament (yes, even the boring parts). I'm so glad I did.
My parents aren't religious and I didn't grow up going to church at all (except for that one year we went to the Unitarian church in town), although I did read my way through some children's bibles and attended the occasional Sunday school class or church service with my grandparents or wedding of one of my mom's many cousins. My lack of familiarity with the Bible wasn't generally a problem until I went to college and became an English major. Regardless of how you feel about God and Jesus, the Bible, and particularly the King James Version of the Bible, are exceedingly influential. Writing those papers and figuring out Paradise Lost would have been way easier with a little more background informtion.
Now I'm still not a churchgoer, but I do work for a seminary and have a great affection and appreciation for theological study, pastors, and seminary students, all of which rely heavily on the Bible. If nothing else, having the experience of having read the whole damn thing lets me understand some of their jokes a little better and have at least a fighting chance of guessing if a certain book is in the Old or New Testament.
I'm not going to lie, there is some rough going in here, especially in the Old Testament. The long lists of begats and genealogies and families with unpronounceable names aren't exactly page turners. The very very detailed instructions on how to build the tabernacle and how to sacrifice what animal when get old pretty fast. And the rules. My god, the rules. Some are funny, some are horrifying, and some are just extremely dull. Of course, the OT also has a lot of battles, kings, power plays, and some truly excellent characters (Moses! David! Saul!).
I can also see why the New Testament is so appealing. When you turn that corner into the Gospels you get one of the most naturally described characters in the whole sacred text: Jesus. And hearing his story four times from four different writers just helps hammer the point home. This is a great story, a revolutionary guy, and a huge change from business as usual. I'm the first to admit that Christians have been pretty horrible over the years (I was in a meeting with an Old Testament professor who said, "the history of Christianity is basically a series of good intentions with pretty crappy results"), but the original story is refreshing, moving and absolutely some good news.