Andrew Hickey (in-universe)

In one universe within the 10,000 Dawns, Andrew Hickey was the man who wrote Head of State, a novel in a preexisting series dealing with a mysterious cosmic war, published by Obverse Books. Published in the early 21st century, the book became a favourite of Graelyn Scythes after she first read it in 2471. (PROSE: Head of State)

Like other books in the series, Head of State was an a coincidentally accurate summary of events which happened to Rachel Edwards in another universe as part of the War in Heaven. (PROSE: Rachel Survived, Head of State) When Graelyn later met Rachel in person, finally being able to tell her how much she had meant to Graelyn as a character to look up to, Graelyn implied that Hickey may also have existed in her own universe, albeit without writing Head of State — reminding her that he'd also written "that book about the Monkees". However, Rachel was unfamiliar with the name or book; Graelyn chalked this up to Hickey not having been "appreciated in his own time". (PROSE: Rachel Survived)

Behind the scenes
This Andrew Hickey is an in-universe acknowledgment of the real-world writer. The "book about the Monkees" mentioned by Graelyn Scythes is his non-fiction book Monkee Music.