I think I've pretty directly disagreed with: > focus on clarity first and only optimize for performance if absolutely necessary I think that in a lot of very

I think I've pretty directly disagreed with: > focus on clarity first and only optimize for performance if absolutely necessary I think that in a lot of very important, very common use cases (take your pick: game engines, embedded programming, OS development, language runtimes, linear algebra libraries, etc. etc. etc.) this is extremely bad advice. It's... probably good advice for enterprise applications; but that's a pretty small subset of all software. I think that if you start with clarity here and do performance optimization after the fact you will build something that can't be used as intended--almost always (of course, not "alwaysly", see Python). More broadly, I think this is a far too narrow way of looking at "clarity" vs. "performance". I have some idea of what I think clarity is, and I have some idea of what I think performance is, and they're both pretty nuanced and deep topics. I think they're two big bags of variables in an even larger bag of engineering variables, and I think Fowler does us all a huge disservice when he skips that entire discussion with what is your synopsis up top there. Maybe you're writing Python and you need a certain level of dynamic nature in order to reach your desired level of flexibility and clarity. That can be fine! The point here is that these are rich topics, and they deserve better than what I see as a pretty blithe dismissal.