The Rise and Fall of D.O.D.O.: A Novel by Neal Stephenson and Nicole Galland (2017).
TL; DR: a time-travel story that makes a LOT of sense (though not quite completely). If Stephenson and Galland (S&G) write a sequel, I will definitely get it.
DODO is an acronym for the Department of Diachronic Operations, which is a bureaucratese way of saying time travel (dia = "through"; chronic = "time"). Dr. Melisandre Stokes literally bumps into DODO's chief liason, Major Tristan Lyons, while he is exiting her boss' office in the Harvard University language department. Tristan was looking for a language researcher with a wide range of older languages but had been basically ejected from Dr. Roger Blevin's office because of his peculiar demands. Fortunately on Melisandre's side, she had been rather unhappy with her minimized role at Harvard--especially with Blevin's commandeering credit for her work--and was thus willing to at least listen to Tristan's offer.
While Tristan is governmentally standoffish in providing details to Mel (everything and every explanation is "classified" which even included what the acronym DODO stood for), what she does eventually learn is that DODO's primary objective is to figure out why magic--the real stuff involving witches, not magicians--had existed throughout history but eventually disappeared in 1851. I'll leave the full explanation of that to S&G, but eventually this leads to an encounter with an eccentric genius from MIT who had tried to create a device which might allow magic to operate in the 21st century despite those problems, but of course his main problem in getting this device to fully work was the lack of any current practioners. Even though there are plenty of witches still around--in fact that MIT eccentric's wife is a descendant of one of the Salem witches who stood trial in the 1690's--there is no one now who is practiced in witchcraft when Mel is contacted by someone who claims to know Mel and Tristan and DODO, AND says she is a witch. While understandably put off by someone they dismiss as a crank (though wondering how anyone outside their small circle could have even the slightest notion of what DODO is up to), Mel and Tristan eventually meet with Erzebet Karpathy who is an elderly woman living in a nearby hospice. Erzebet tells Melisandre that she had talked to Mel in 1851 (time travel, remember?) before the magic had gone away, explaining that Erzebet and her mother had cast a long-life spell which had allowed her to last to about 180 years old while undergoing considerable efforts to avoid being noticed by the authorites or "The Today Show" for her extreme old age.
While put off by her rather commandeering presence but having no other explanation of Erzebet knowing about DODO, Mel and Tristan decide to allow her into their relatively small experimental device which rather ironically requires a huge amount of high-tech gear to create that small space for Erzebet to practice her magic, which she performs spectacularly because she emerges from the chamber rejuvenated into the body of a gorgeous 20ish woman (Erzebet would have explained this as just returning herself to what she had been at that age).
Naturally the bureaucrat in Tristan requires Erzebet to conduct a long series of trivial experiments--changing the color of something from red to blue--until his commanding general comes to the DODO offices asking if Erzebet can do anything "real" like travel through time. She obliges, sending that general back to a 16th century Hungarian village close to the one in which she grew up during the early 19th century. There are complications because her magic could only send back his actual body which meant that EVERYTHING not part of his body like his clothing, his dentures and fillings, his artificial leg, and his pacemaker were left here, but there was a short passage that appeared in Wikipedia reporting about a naked, aged, one-legged warlock who suddenly appeared in the town square speaking only gibberish (unfortunately that general knew no Hungarian). He was quickly burned to death.
Having demonstrated this ability though in a rather tragic episode (the general was memorialized as having died in line of duty), the story of DODO can really begin.
Let me use this small example of how the novel makes some sense of time travel. One part describes how people are being sent back in time and then returned to current day, but the process is somewhat complicated by how if a time-traveler spends, say, 6 days back in time then she would be returned only 6 days following departure. Naturally there is an effort to get the witches (because a witch in the past is required to return the traveler to the present) to "time-compress" the journey by sending her back to a point only minutes if not seconds after departure. Erzebet reacts to this notion with absolute horror, so it is only through a lot of cajoling that an explanation emerges: the witches consider the two spells to be completely different. While the spell to send someone through time takes a lot more effort and study to be performed correctly, the spell to return someone to their original timeline is seen as just that: a restoration spell returning a person to her proper time. If the traveler had aged 6 days during her time-travel then her proper time in the present MUST be 6 days following when she left. To do such a time-compression for time travelers would require that witch in the past to create an entirely new spell rather than an "easy" restoration spell.
Part of Erzebet's horror is due to the phenomenon of what is called in the novel "diachronic sheer". While SOME subtle changes in history could be made making use of the so-called
butterfly effect, there is something which could be called a "conservation of historic momentum" in which any drastic change in history must be corrected, sometimes with devastating effects surrounding the change. Let's say a time traveler wanted to prevent JFK's assassination by stopping Oswald from getting into the Dallas Book Depository. Diachronic sheer might correct this by causing the front part of that building to explode outward, killing the president (along with a lot of bystanders) and someone--maybe Oswald--would get the blame of setting off that bomb which caused that explosion (because there MUST be an explanation, right?). So from Erzebet's POV any attempt at such time-compression as suggested by others at DODO could result in DODO itself vanishing in an unexplained explosion ("It must've been a gas leak?") to prevent that from happening.
In any case, this is a fun read and I highly recommend it.
