How does a retired author report royalty income from past work he is not actively involved with?

[MindyB]

From the information you provided, the income from the royalties received on the sales of your books/other media should be reported on Schedule E. This is because you are no longer regularly engaged in operating a business with the primary purpose of profit. ‌

You should choose the first option when entering your 1099-MISC  "Royalty investment income from a natural resource, intellectual property or other investment portfolio." Depending on which option you choose, the income will be reported on a different schedule on your tax return.  The first option, "natural resource or intellectual property" will flow to Schedule E, while the second option, "being self-employed as a writer, inventor, artist" will flow to Schedule C.

Here are the instructions for reporting  How do I enter a 1099-MISC for royalty income?