A recurring plot in Star Trek features people from the past coming forward into the 23rd or 24th century and encountering our heroes, who must help them adapt to their new reality. Whether these people are genetically-engineered despots (as in “Space Seed“) or a random cross-section of humanity (as in “The Neutral Zone“), it is a common trope that has been done a number of times in televised Trek. There are some interesting elements that stem from the use of this trope in Across the Universe. For one, one of the 21st century humans the Enterprise recovers is a distant ancestor of Pavel Chekov. I found the gradual uncovering of his character and the implications it has for the muddying of history to be a fascinating aspect of the novel, and I can only wish that this idea had been explored more.