"Who knows whether in retirement I shall be tempted to the last infirmity of mundane minds, which is to write a book"

This quote by Geoffrey Fisher is a reflection on the potential of his future. He is wondering if he will catch the "last infirmity of ordinary minds" which is to write a book. This suggests that he understands the tendency of some people to compose a book as a method of revealing their thoughts and ideas. He is likewise knowledgeable about the potential pitfalls of such a venture, as it can be a time consuming and difficult task. He is uncertain if he will be tempted to take on such a task in his retirement, however he is open to the possibility. This quote reflects his thoughtful and introspective nature, as he is thinking about the potential of his future and the potential of composing a book.