The “Author’s note for the definitive edition” appended to the paperback of Black Helicopters clarifies that it was written prior to the novel to which it has since been published as a sequel, Agents of Dreamland. Although the Signalman from Agents does make an appearance here, it is only in one chapter, composed after the main text and after Kiernan had decided to connect the stories. Immacolata Sexton does not appear. This book features shoggoths, rather than the mi-go of Agents, but it’s really the humans who are creepiest in both books.
Black Helicopters doesn’t actually feature helicopters very conspicuously, and the narrative is non-sequential and all over the map: jumping between 2001, 2012, 2035, 2114, 2152, and other dates more difficult to decipher. Its ludic theme is grounded in chess, more particularly, the chess of Lewis Carroll’s Through the Looking Glass, while scientific themes include chaos theory, quantum physics, and paleontology. This last topic is one of prior professional interest to Kiernan, who has worked in the field. In fact, she admits to a strong autobiographical streak in the paleontological characters, crediting them with her own scientific achievements (and getting paid back in their glamorous outre narratives).
I think I preferred the shorter and more focused Agents of Dreamland to Black Helicopters, but this book was still a pretty quick read and a lot of fun. It will be best enjoyed by those who can appreciate the author’s scientific and cultural allusions, and who like terse, cautious dialogue among mistrusting interlocutors. The appended “remix” of Chapter 9 supplies the English for a conversation that the body of the book presents only in French. Since the chapter is set in the future relative to most of the rest of the book, non-Francophone readers will appropriately read it only after coming to the end.
Since the “series” relationship of this book to its other seems to have been an organic happenstance rather than deliberate plan, I only hope that it has inspired Kiernan to work on further stories in the same continuum.