First, your high school history curriculum is fantastic. I went to school in one of those stereotypical southern states and the history classes were "taught" by coaches in their spare time. I didn't get any substantial history education except through personal reading and later in college. Kudos to the Irish education system; I'm envious.

Second, my college major was political science with a minor in history, so my recommendations skew in that direction. I was fortunate enough to have an entire course in college on just the Red Scare, so I'll put a couple good books from that class on the list.

I'll put Amazon links, but I'm sure you can find them at a library for free. None of these are obscure books.

Nightmare in Red: The McCarthy Era in Perspective, by Richard M. Fried. This was the first book I thought of, because when I first red it in college, I knew *nothing* about this period in American history. I'd never heard of the Red Scare, Hollywood Ten, Blacklist, or any of it. It opened my eyes to how ignorant I was. The book itself gives a thorough account of the rise and fall of McCarthyism and this era in politics and culture.

Inside Out: A Memoir Of The Blacklist, Walter Bernstein. Another one on the Red Scare - this time focused on the Hollywood Blacklist. The author was blacklisted in the last 1940s, and tells his story, about the rifts in the entertainment industry, how blacklisted entertainers / writers / etc. survived and had careers in the shadows, and really brings the human impact of this era into focus.

The Presidential Difference, Fred I. Greenstein. Each chapter focuses on one of the presidents in order, from Franklin Roosevelt. Gives a concise overview of their term in office, background info about them, and the author then gives his assessment of their legacy, significance, political strengths and weaknesses, communication skills, cognitive style, etc. It culminates in the author's discussion of what he thinks it takes to be a successful president in the modern world.

The edition on my shelf only goes up to Clinton, but it appears there's an updated version that goes through Obama. Makes me want to buy the new one to see if/how he's revised his assessments.

The Cycles of American History, Arthur M Schlesinger. It's a prominent historian's thoughts on how America's national character developed and evolves over time. Spans much more than just post-war history. And while it's not properly academic, it's definitely not pure entertainment. It was a thought-provoking read.

Gideon's Trumpet: How One Man, a Poor Prisoner, Took His Case to the Supreme Court-and Changed the Law of the United States, Anthony Lewis. Tells the story of Clarence Gideon, a poor, uneducated, petty criminal who successfully fought to establish the right to an attorney in criminal cases. Before this case, if you were too poor to hire a lawyer, you simply didn't have one. This case is why, when arresting someone, the police now say "if you cannot afford an attorney, one will be appointed for you." It's a corner of US history I didn't know, and the book was well written and engaging.

Summer for the Gods, Edward Larson. This one is a bit before your target timeframe... but the cultural division it's about is still very relevant in American politics and identity today. In 1922, the state of Tennessee passed a law forbidding the teaching of evolution in schools on the grounds that it's anti-religious and contradicts the Christian creation story in the Bible. A teacher gets arrested for violating that law, setting up a trial that pulled in prominent politicians, journalists, attorneys, and national organizations. A tiny town in Tennessee ended up hosting a giant show-trial that gained national attention, essentially putting science and religion on trial against each other. It's a relatively short book, with some delightful (real) characters in it, and a pretty easy read. The religious/scientific divide it showcases is still very relevant today.

Hope this is helpful - enjoy!