This is a very passive way of generating income, but the catch is that you need a lot of money to build this passive income machine.  For example, you find a combination of dividend producing stocks & bonds (this also can be done with CD’s (and other cash equivalents) that you are comfortable with, the yield (or passive income) generated on the portfolio is 5%.  In order to generate $50,000 a year in passive (dividend) income you would need $1,000,000 in your account.  (CDs are FDIC insured up to $250,000 per depositor per insured depository institution.)
Try going to our post: 20 Sites That Will Pay You to Read Books: Even though editing is not what this post is about, there are several companies that might do book editing such as Kirkus: I hope this helps and good luck on your book!