"Inside the Mind of BTK" by John Douglas

Link: https://www.amazon.com/Inside-Mind-BTK-Thirty-Year-Notorious-ebook/dp/B000UZJR86

If you're like me and you're fascinated/disgusted by Dennis Rader, this was absolutely phenomenal. I can never focus on anything and I tore through this book. It's by John Douglas as well, so it has a Mindhunter-esque vibe to it.