The Ghost in the Machine: The Ethics of Writing for Another Author

Among my job prospects this past month is a position ghost writing a book. I'm great with research and writing, but this just seems like cheating to me. Here's why:

The research is hasty and I'm not allowed to quote sources. Knowing little about the topic means I would normally rely on sources to back me up. I'm doing the very best I can to write everything I learn, being very thorough and not copying the work already done by others, but I'm not an expert on the topic and I question whether I would buy a book researched and written in two weeks by a person who has just learned the very basics.

And here's the kicker:

The client has accepted every draft of the project without any major revisions!

Now, I'm wondering who this guy is trying to cheat. And that's what lead me to questioning this whole idea of ghost writing.

What are your thoughts? Is ghost writing unethical? And who should be accountable, the client or the writers?