I love time travel stories, so much so that I’m not very picky about how good they are. This story of two friends who travel in time, originally to find a missing father but later for entertainment, isn’t in the first rank of time travel stories. It doesn’t deliver the sense of strangeness at encountering another time that is, for me, an essential element of the genre. What it does offer is an unusually original plot element: the profligate use of the characters’ machines to avoid or correct the smallest error or inconvenience. Raining on your arrival in Renaissance Italy? Come back in a couple of hours. This leads to all sorts of interesting situations and makes the whole book, despite it’s faults, a lot of fun.