@littlek,
Ah, sorry you got unlucky there; all the Oliver Sacks books I've read so far
were written for laymen. I hope it's still worth the effort?
***
Niven's
N-Space is a much slower read than I expected as well, but for a pleasant reason: Because the book is an anthology, every story presents a new world Niven made up, or explores a new corner of a world I already learned about in an earlier story. Accordingly, after about five pages of diving into a something new, my reading gets abruptly interrupted by a thought like "but what if ____?", or, "I wonder what ____ might work like?" And then my thoughts wander off on their own for a while. So it's five minutes of reading, thirty minutes of thinking, five minutes of reading, thirty minutes of thinking.... At this rate, it will take a while until I finish.