I don't think it's fair to compare 'Refactoring' and 'Design Patterns' based on their respective number of pages. They are both catalogs, but they are catalogui

I don't think it's fair to compare 'Refactoring' and 'Design Patterns' based on their respective number of pages. They are both catalogs, but they are cataloguing different things. A design pattern IMO is harder to explain and understand than a refactoring, it needs to provide some context, and by definition you need to prove that it qualifies as a pattern by showing a few examples found "in the wild". Also, the authors had to show how these patterns can be implemented in different programming languages (Smalltalk and C++). Fowler could get away with one simple example of a refactoring in Java each time. Having said that, Fowler's prose is super clear, something that cannot be necessarily said about GoF, (IMO of course)...