* Adverb: "The author wrote a brief summary of the book."
* Adjective: "The detailed summary helped me understand the main points."
* Adverb: "The teacher gave us a clear summary of the lesson."
* Adjective: "The book had a confusing summary, making it hard to follow."
You could also use a compound adjective like:
* "The short and sweet summary was perfect for a quick review."