‘Cerebral’ science fiction recommendations please.

[Foghead]

I really want to think. About technology, science, space and mankind (or any ‘other’ kind)
Can anyone recommend anything please?

James Tiptree is brilliant (depressing, but brilliant) - mainly wrote short stories in the 1970s. Her Smoke Rose Up Forever is a good collection & available on Kindle.

Neal Stephenson's books are usually fantastic and brainhurty:
Snow Crash
Diamond Age
Anathem
Seveneves

Three-Body Problem and its sequels - These are the most brainhurty, incredibly imaginative and think-hard SF of recent years. Heartily recommended.

William Gibson - Father of cyberpunk subgenre of SF, but he was overshadowed by N Stephenson imho. He's good on Twitter, though. I'd recommend his earlier books:
Neuromancer
Mona Lisa Overdrive
Idoru

Dan Simmons:
Hyperion
The Rise is Hyperion
(Further sequels Endymion and Fall of Endymion are not as great imho)

Another recommendation for 3 body problem trilogy. My mind boggles that people can come up with these stories

If you get a free trial of audible you can download and listen to it (and many other great sci fi books)

The three body problem did my head in. The first volume was absolutely brilliant, ground breaking, mind blowing. The second two, I had to force myself to finish them. The female character was just so utterly awful.

"The three body problem did my head in. "

Yes, that's what cerebral SF does

Whether one character is 'awful' or not is neither here not there. It doesn't make a book great or terrible.

L E Modesitt has some fantastic sci fi books, very complicated in places. Gravity dreams and the parafaith war are my favourite.

The first fifteen lives of Harry August by Claire North is sci fi with a lot of quantum physics and philosophical musings on the meaning and purpose of life!

Great story too

I agree with L.E. Modesitt novels. His books are amazingly written and thought provoking but unfortunately he is not the most popular author despite having a bit of a cult following.