Pick up No Man Knows My History by Fawn Brodie. You can check out the footnotes to check her sources. She was David O Mckay's niece and was a fine historian. This book is a bio of JS and will give you a whole new perspective about who JS was. It is not snarky or anything. She just lets you know all the things you didn't learn in Sunday School about him and the origins of the church.
The LDS considers this book to be very damaging (lies, lies!). For the official rebuttal (by Hugh Nibley) they published a pamphlet called "No Ma'am That's Not History." This response is probably the most damning admission that Brodie got most things right. They attacked her personally and only rebutted a few very minor details.
You are just hitting the tip of the ice burg. You will be amazed just how much humans revise history to support what they want to believe.
Next stop, "Age of Reason" by Thomas Paine. Short and to the point comments about the Bible. A classic.
But don't stop there. "Demon Haunted World" by Sagan will open your eyes about what standards to hold when people make claims. He has a bologna detection kid in the book.