The first book in the Camelot Code series, The Once and Future Geek , mixed time travel between the medieval world of King Arthur and our own, and it is a very entertaining book. The second book in the series, Geeks and Holy Grail (Hyperion, October 2019), is also entertaining (though not quite as funny; King Arthur as a modern day high school student is hard to beat....). When Morgana, sworn enemy of King Arthur, attacks the druids of Avalon, Nimue, the youngest of them, takes the Holy Grail and runs with it. King Arthur is dying, and only the Grail can save him. Desperate to keep it from falling into Morgana's hands, she stumbles into Merlin's Crystal Cave. But instead of Merlin there to help her (he's on vacation in Los Vegas, in our time), there's only his very inexperienced apprentice, Emrys. His attempt to hide the grail works, in a sense--as a small, flatulent dragon, it sure doesn't look much like a grail. But it isn't much use to Arthur as a...
One Word Kill, by Mark Lawrence (47North, May 2019) , is a time travel story in which changes to the past create multiple timelines. It's the story of 15 year old Nick, a math genius who enjoys playing D. and D. with his three buddies, and what happens when a girl, Mia, joins the game. It's the story of Nick finding out he has cancer. These concerns, even the fact that Nick might be dying, are back-burnered when a strange man starts stalking Nick, telling him that Mia is in danger and needs his help. Saving future Mia involves a dangerous heist, and it also involves surviving the violent attentions of a gang of drug-dealing thugs, one of whom is a true psychopath. Fortunately, the strange man is there to help when things get really ugly. Turns out (and this isn't much of a spoiler, because it's told to the reader fairly early on) that this stranger is Nick from the future, come back to save future Mia. Though his timeline's Mia might be in jeopardy, ther...