noun
stupid book; worthless book
Derogatory term for a book of poor quality or content. Not a humble self-reference.
あの作家の新作は、まったくの愚書だった。
That author's new work was a completely worthless book.
noun
my poor writing; my humble book; my letter
Humble self-deprecating term for one's own writing, book, or letter. Used in formal or polite contexts to show modesty.
愚書をお送りいたしますので、ご笑覧ください。
I will send you my humble book; please take a look.
先日は愚書に目を通していただき、ありがとうございます。
Thank you for looking over my poor writing the other day.