As others have said, expert-level material tend to not lend itself well to a book format.
Instead I find a lot of advance level knowledge is usually shared in tech blog posts and tech talks. The quality of these tends to vary a lot, so you need a bit of curation and due diligence. I myself found the videos from InfoQ very useful with 15 yoe (particularly in the software architecture track).
And if you want the really advanced stuff, you can also read papers. The barrier to entry is higher and sometimes is difficult to connect them to your everyday problems, but it doesn't get more cutting edge that than.
Instead I find a lot of advance level knowledge is usually shared in tech blog posts and tech talks. The quality of these tends to vary a lot, so you need a bit of curation and due diligence. I myself found the videos from InfoQ very useful with 15 yoe (particularly in the software architecture track).
And if you want the really advanced stuff, you can also read papers. The barrier to entry is higher and sometimes is difficult to connect them to your everyday problems, but it doesn't get more cutting edge that than.