I'm looking forward to Andy's book too. It would be great to think that he had the time to actually pen it himself, but most sports autobiographies are at least partially ghost written. Assuming this is the case here, I wonder who Andy used to help him. Neil Harman perhaps? (I have no actual knowledge, just hypothesising....)
I remember reading something with Andy,where he was talking about putting together the book,and he said something like "I've been spending a lot of time with Neil Harman lately",so sounds like Neil was involved.I'm trying to remember where I saw the quote,as there was more to the answer-I'll think some more about it and hopefully it will come to me!
Edit: Found it!At least,I think this is it.
"TENNIS.com: You’ve got another book coming out in November? Is that right?
MURRAY: Yes. Hopefully, if it gets done in time. Neil Harman—I’ve spent a bit of time with him over the last few weeks. It’s not an autobiography, it’s more a sort of picture book. But there was a few books after the U.S. Open last year that came out—unofficial biographies and what not. I think it’s important when that starts happening to kind of do your own thing with your words and make it more official."