The Starship Chief is free (on Smashwords), but not public domain. All rights reserved, as it’s a novella inspired by Treasure Island, King Lear legends before Shakespeare and the film Treasure Planet. However, while stand-alone and 25 years before The Apprentice’s Talent, it does need to be read before The Master’s Talent. Do not share it or upload it. Anyone may freely download it (anonymously, no sign-up) for Kindle, Nook, Kobo or eReader applications*.
* I recommend Aldiko for Android (doesn’t spy like Kindle App) and Calibre to manage your books. There is a way to convert Amazon eBooks downloaded to transfer via USB using Calibre, for your own use on Aldiko App, Nook or Kobo, if you own an actual Kindle.