Modern scholarship suggests that the Pentateuch was not written by one single person, therefore it cannot be said to be written by Moses. There are multiple versions of several stories in the "Books of Moses," not to mention the fact that the book of Deuteronomy tells of the death of Moses. Its kind of hard to write of your own death.
Now I am Christian, and tradition states that the first five books were written by Moses. And while that is a pleasant thought, I really don't think Moses had that kind of time on his hands, he probably had a lot of stuff to deal with. And others who comment on this debate, just answer the question, don't state your opinion on how ridiculous this stuff seems to you.
The first 5 books of the old Testament were written by 5 different Authors over different ages around 950BC to 500.
Interestingly, the Genesis creation account was written by the last writer 500 BCE.
Find out more at https://en.Wikipedia.Org/wiki/Documentary_hypothesis
For all Christians, do you believe a random person, that says he has a message from God as Joseph Smith?
Then why trust the writers of a book who lived 2500-3000 years ago?