They are all revisions of existing short stories he previous posted for free on his website, which are linked here, as well as purchase options.
► Lena - Cautionary tale of the first human brain upload being duplicated, incidentally tortured (for compliance) hundreds of millions of times in increasingly numerous parallel simulations, to use him as a cheap information processing commodity.
Qntm preciously threw this into Fine Structure Constant, in passing. It's a sobering thought for extropians like myself, intent on digital reincarnation with indefinite lifespan. But, I feel like ChatGPT and other generative AI are already making redundant this idea of simulating brain Uploads for such utilitarian purposes. It's gonna be many orders of magnitude less efficient and probably less reliable.