Ask HN: How do you read non-fiction books?

For example, I recently bought `Designing Data-Intensive Applications` by Kleppmann, it's quite a thick book (for a reason). How would you approach reading a book like this? I had a same problem with `Code complete`, obviously it's a bit different when it comes to size comparison, but generally strategy should be same (oh and I feel like I didn't learn nearly enough that I should/could have). It took me quite a bit of time to read it as well, as I was reading it after work/weekends. I have this threshold that I want to remember at least ~70-80% of the book that I invest a lot of time in. But it sort of seems infeasible to me least, without investing too much time. Thanks in advance.