The dedication, you didn't say,

当时的献辞里不会说
dedicated to so and so, what you said was Dear Theophilus,

献给谁谁而是说亲爱的提阿非罗
I am writing this because you've asked me to set down my thoughts.

按你的要求我写下自己的想法
In other words you give a fiction,

换句话说你想写部小说
it's a fiction that your patron,

一部由你的资助人
maybe the person who supports you financially or socially,

可能是一个在经济上或社交上支持你的人
or whatever that person has asked you

这个人要求你写下来的
to set down an account of something.

关于一些事情的记录
You would start off, "Dear Mr. Smith you've asked

你会这样开头 "亲爱的史密斯先生
me repeatedly when we had lunch at Mori's,

你周一在莫里饭馆用午餐时的反复要求我
to describe my recent trip to Africa,

描述最近在非洲的旅程
so I'm writing this down at your request.

所以我按照你的要求写下来