A father mysteriously slips through time in Joseph Eckert’s The Traveler Mikhail Rudenko / Alamy Writing this as the UK swelters under an unprecedented May heatwave, perhaps it’s small wonder that so many science-fiction authors are currently imagining miserable versions of an overheated future in which their characters are struggling to survive. I’m intrigued by the sound of sci-fi legend M. John Harrison’s upcoming take on a dystopian future, but if post-apocalyptic hellscapes aren’t your thing, I’m also happy to report that there are other options for sci-fi fans this month. I’m already enjoying time-travel adventure The Traveler by Joseph Eckert. Next, I’m going to explore Isabel J. Kim’s sci-fi spin on immigration, Sublimation , as soon as I can get my hands on it. And then for a little light relief, I’m planning on lining up Adrian Tchaikovsky’s Green City Wars . The End of Everything by M. John Harrison I am excited about this book: M.…