Blackshirts and Reds for sure. That book opened my mind with a goddamn crowbar. I can easily say that my political thinking has a pre-Parenti and a post-Parenti phase. It's also an incredibly easy read, and there's always the yellow lecture as a complement.
In addition to that, I'd recommend JT's videos on Second Thought. They're very very accessible and unbelievably well-produced. Our good ol' Texan boy is a great communicator.
It's optimal for people who are already disillusioned about liberalism but haven't yet come over to full communism.
I found a YouTube link in your comment. Here are links to the same video on alternative frontends that protect your privacy:
BLACKSHIRTS AND REDS BLACKSHIRTS AND REDS BLACKSHIRTS AND REDS
Bullshit Jobs is my first recommendation for anyone who is starting to gain some introspection.
https://en.prolewiki.org/wiki/Library:How_Marxism_works this is how I came to communism
Yellow Parenti https://www.youtube.com/watch?v=xP8CzlFhc14
Not yellow Parenti https://www.youtube.com/watch?v=tgTWnUpvNiM
Another Not Yellow Parenti https://www.youtube.com/watch?v=TOBRRBJyowo&t=5s
Also not yellow parenti https://youtu.be/OOF56wYTl1w
https://youtu.be/uThpIDlfcBQ 
I found YouTube links in your comment. Here are links to the same videos on alternative frontends that protect your privacy:
Link 1:
Link 2:
Link 3:
Link 4:
Link 5:
These might not exclusively deal with capitalism but:
- Robert Reich - Beyond Outrage: What Has Gone Wrong With Our Economy And Our Democracy, And How To Fix It
- Zygmunt Bauman - Globalization: The Human Consequences
- Chris Martenson - The Crash Course: The Unsustainable Future Of Our Economy, Energy, And Environment
- Jeff Rubin - The End Of Growth
- Heather Marsh - Binding Chaos: Mass Collaboration On A Global Scale
- David C. Korten - The Great Turning: From Empire To Earth Community
- Daniel Quinn - Beyond Civilization: Humanity's Next Great Adventure
- David C. Korten - Change The Story, Change The Future: A Living Economy For A Living Earth
- Alfie Kohn - No Contest: The Case Against Competition
- Stephanie McMillan - Capitalism Must Die [anatagonistic title but a great read]
- Adam Buick & John Crump - The Alternative To Capitalism
- Annie Leonard - The Story Of Stuff
- Jacque Fresco - The Best That Money Can't Buy / Designing The Future
Robert Reich also has the benefit of being in the Obama Admin, so most liberals don't have a reason to outright dismiss him. Obviously he is still either quite naïve, or he is hiding his power level very well, since he keeps talking about union-membership as the end-all-be-all of fighting capitalism, but hey, it's a start.
https://github.com/dessalines/essays/blob/master/crash_course_socialism.md
I feel like we need more of this style.
