Radiance is the story - or a story, or many stories - of Severin Unck, the daughter of celebrated filmmaker Percival Unck, who disappeared while she working on a documentary about the unexplained destruction of a small diving village on Venus.
Because the book is set in a solar system very different to our own: in which we reached space in 1858 and found not eight barren rocks but worlds teeming with strange indigenous life - though none approaching sentience, save perhaps for the mysterious Venusian callowhales, whose milk (which may not be really milk) is essential to sustain human life on the planets of the solar system, protecting human bone density in the different planets' gravities. The present day of the book - although it's spread out over several decades - resembles the early years of film in our world: Edison has patented the use of colour and sound in film, meaning that both are prohibitively expensive to use, so most films are still shot in black-and-white, and are silent.
So Radiance is a sort of post facto reconstruction of the story of Severin's disappearance, as her father struggles to make a film of the disaster and come to some sort of closure. It's told in bits and scraps of evidence: the little film that remains from the Venus expedition, interviews with the crew who were there, the stories Percival tells to himself to try to make sense of it all. It reminds me a little of Night Film, and a little of House of Leaves, only mashed together with Valente's lushly hypnotic prose and world-building. I've seen it called decopunk, which is probably as close to a decent description of its aesthetic as I can think of.
It's a book that weaves together several storylines, and doesn't come up with any hard-and-fast answers; it's partly about the human attempt to make lives seem story-shaped even when they aren't.
Whatever else it is, it also feels very glamorous in its evocation of early Hollywood. It pays a lot of attention (unsurprisingly) to the visual aspects of Valente's bizarre world, especially to colour, or the lack of it. I just wanted to inhale it and then live in it forever; it's a world that feels utterly real and rich and exciting and also tragic and sinister.
If I could read Valente all the time I would.