me_irl

i always recommend mindfulness in plain english by by Bhante Gunaratana as a start. not sure what you mean by "nonsense," but this book is just method: how to let go of things and find peace, where before we wouldn't even realize we just spent the whole day dwelling on something that irked us that morning, and can't figure out why we're so pissed off at bedtime. we're not paying enough attention to realize we're not paying enough attention. it sounds like a simple thing to fix but it's not remotely easy--people spend lifetimes working on this.

because psychology and mental processes are so subjective, it's different for everyone--the "facts" you'll find will be personal testimonies (thousands of years' worth). but there are studies if that makes it more "valid" for you.

I've always really liked Jon Kabat-Zinn. His secular view of mindfulness is very palatable for folks who aren't as much into the "woo woo" aspects of spirituality. His book Wherever You Go There You Are is a great introduction.

I'd add that part of my personal journey has been from someone who was radically anti-woo woo to someone who without judgment accepts that there are others who choose to practice different types of spirituality from me (as long as they aren't hurting others with their beliefs or practices, I'll mindfully tell those people to get fucked)