Splitting earnings from book
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This will be my second published book.
The first one was published by an editor and got me some interviews on the radio, TV, etc. I think this background is what will allow me to publish this second book.
This second book is an essay about my (38F) friend's (70M) profession, which will explain my story and his during the 2 years I've been working with him. I would say 70% of the book is based on things he has explained to me while we were working. He knew I was recording him for this book. It took him around 20 hours of sharing information with me.
The thing is that, to give all that information some kind of sense, I've had to interview more people, study the topic, visit another country to understand the context of this profession, verify all the data he has given (which is sometimes not accurate)..., and then there's the work of defining the storyline, creating all the literary characters, and writing his raw, chaotic message appealingly. I think it will take me 1-2 years of work and approx 600€ in expenses (trips, proofreading).
We won't be paid much, but my friend is expecting to divide the earnings by 50% each.
I think he doesn't understand all the work that goes into creating a story and publishing a book. He also thinks I can write this book because of him (which is not exactly true; I could choose another main character).
What do you think would be a fair division?