Eric Evans' Domain-Driven Design: Tackling Complexity in the Heart of Software was a challenging read.
I read it as part of a book club, but I struggled quite a bit. There were many parts I couldn't fully digest.
I came to understand that DDD emphasizes the importance of understanding and interpreting the domain itself, rather than focusing solely on how to represent it in code.
I find the process of understanding the domain before translating it into code to be the most challenging part.
I plan to revisit this book after some time.