May I recommend https://sites.psu.edu/ehssan/wp-content/uploads/sites/7257/2013/10/Atiyah-Mathematics-in-the-20th-Century.pdf https://sites.psu.edu/ehssan/wp-co

May I recommend https://sites.psu.edu/ehssan/wp-content/uploads/sites/7257/2013/10/Atiyah-Mathematics-in-the-20th-Century.pdf https://sites.psu.edu/ehssan/wp-content/uploads/sites/7257/2..., a transcript of a 2000 talk by Michael Atiyah? A tiny bit from section 9: > The 20th century can be divided roughly into two halves. I would think the first half has been dominated by what I call the "era of specialization," the era in which Hilbert's approach, of trying to formalize things and define them carefully and then follow through on what you can do in each field, was very influential. As I said, Bourbaki's name is associated with this trend, where people focused attention on what you could get within particular algebraic or other systems at a given time. The second half of the 20th century has been much more what I would call the "era of unification", where borders are crossed, techniques have been moved from one field into the other, and things have become hybridized to an enormous extent. I think this is an oversimplification, but I think it does briefly summarize some of the aspects that you can see in 20th-century mathematics.