Info on ghost writing ones memoir

col

I have a friend who is intersted in ghost writing my memoir. I feel like I am cheating by having him write it and I get all the credit, but he is fine with that. I'm sure I will get over that soon. The questions I have is:

1 - If someone ghostwrites a story for you, should you and do you need to have a contract? My concern is that if something actually would become of the novel and it ended up getting published, wouldn't he come forward and try to claim the rights to my life story?

2 - If the above is true and you should have a contract with a ghostwriter, does anyone know of a website or link here that shows a sample contract.

I am not asking for legal advise, I am just asking for anyone's opinion or actual experience with this type of a situation.

Thanks in advance for your response.