This was one of the more interesting jobs I have done. Nigel did not want me to help with editing or writing, he just wanted me to create a contest puzzle for him based on his book. He wanted a puzzle, which actually became a series of puzzles that people who bought his book could figure out and solve (for a prize).
This was tricky, but I feel I did a good job with it. The problem is, since I know the answer I can't solve it. Sigh. Oh well, I guess getting paid to do it was my prize.
I make it a point not to review any books on Goodreads (or Amazon) that I was paid to work on in some way or the other. I do not feel it would be fair. My only exception is those books that I work on for an author review service. When I write these reviews I get paid a minimal amount for my time and I get a free copy of the book I am reviewing. Sometimes, I review these to give the author advice (where I do not actually write a publishable review). however, if I am writing a publishable review, I signed a contract stating that I can repost it as long as I tell people that I reviewed it for the service. Since I am disclosing that I reviewed it for a service, I do post these reviews.