Here's a couple of my favorite "readable", no-experience-necessary history books to get you started:

• Diarmaid MacCulloch, "The Reformation: Europe's House Divided" - a sweeping exploration of the Protestant and Catholic Reformations, from their roots in late medieval piety up through the expanion of "Europe" into the New World. MacCulloch subtly builds an argument that the Reformation was a time in history when ideas--not money, not politics, but human reason and belief--changed the world. He doesn't hit you over the head with it, though. For the most part, this is like reading an amazing collection of little stories linked by a head-spinning, globe-spanning narrative.

• Halik Kochanski, "The Eagle Unbowed: Poland and the Poles in the Second War War" - Poland in WW2 is a historiographical minefield where everyone has a perspective and a politicized agenda; /u/commiespaceinvader directed me to Kochanski as the most recent and best attempt to approach the question equitably from both Christian and Jewish perspectives. My request had been sparked by wondering about Gentile perceptions of the ghettos' construction and "liquidations"; I got SO much more out of this book. Kochanski charts the Polish experience from World War I past V-E day, looking at Poland under German and Soviet occupation, carrying the story of Poles in Poland and in exile (in Siberia, in the Middle East, in the French resistance!), focusing on the suffering, collaboration, and resistance of both Christians and Jews. I was stunned to discover how little I had known about the Polish WW2 experience. A stomach-churning, eye-opening, and world-expanding book in all the best ways.

I'm fond of Adam Hochschild's King Leopold's Ghost, an examination of the Belgian Congo, focusing on its founding, the genocide and exploitative rubber trade that took place there, and the efforts of a few individuals to bring to light the horrors that were going on there, which resulted in an end of individual ownership by Leopold and replacement with the Belgian state more broadly (spoiler: this didn't really make things better). Hochschild is a journalist, not an historian, but he cites the right sources and the book has been positively received by historians of the period, including Jules Marchal, one of the foremost Belgian historians working to shed greater light on the atrocities committed there.

For something on ancient military history, I don't think you can do much better than J.E. Lendon's "Soldiers and Ghosts". It's written by a respected expert and covers Greek and Roman warfare in a chronological, accessible and interesting way whether you're a layman or an expert. His views on the role of glorification of the past and masculine competition in driving (for the Greeks and Romans) and also stifling (for the late Romans) military change are by no means the last word on the matter (Wheeler, another top expert and critic, thinks he overreaches a little), but they're interesting. The book is also just a plain good read.

I found David Greens' The Hundred Years War: A People's History to be very readable. It's a very approachable history to the conflict, where he runs through the overall timeline in a succinct but easy to follow manner in the introduction, and then from there focuses on specific aspects of the war in individual chapters. These chapters also happen to focus on events chronologically, though, so while he focuses on themes and cultural topics for most of the work you don't have to also struggle to keep 115 years worth of chronology in your head.

If you're interested in Rome, I'd encourage you to check out Adrian Goldsworthy's books. His style is very approachable and his sourcing is excellent. My personal favorite of his is In the Name of Rome but all the ones I've read are fantastic analyses of Rome. In the Name of Rome specifically goes through several significant generals and how their military brilliance allowed Rome to build her empire. His retelling of the battles themselves is very factual though, so if you're looking for a more argumentative piece of literature you won't likely find it there. Instead, he builds up the generals themselves with their victories and how these men changed Rome's position in the world.