In short: Unfortunately, Dark Mirror by M.J. Putney was unable to capture my interest and somehow managed to make even magic lame and boring. 
 Magic plus time travel. Can't go wrong, right? Unfortunately, much to my surprise and dismay, Dark Mirror by M.J. Putney didn't work for me. It was an amalgamation of things that didn't work but ultimately, I was bored. I couldn't bring myself to care about any of the characters or the plot. Nothing inspired any stirrings of interest; if I was the type to DNF books, I would've done so within the first 50 pages of Dark Mirror. 
 The magical abilities that Tory and her friends have weren't even interesting, which I didn't think was possible. Talk about some of the lamest magical powers ever. One guy is an expert at moving clouds around; one girl specializes in heating things; one guy is particularly good at finding things. LAME. And they seriously thought they were going to be able to take on Napoleon's army with these powers? Don't get me wrong, it's noble and all that they want to fight for England, but they were clearly delusional. 
 I disliked the writing as well but I'm not sure I could put into words exactly what didn't work for me. It seemed a bit amateurish, though I know that's not true because M.J. Putney is a fairly experienced author. I guess I thought the writing was too simple and bare. I'm not saying I need writing to be extremely flowery and detailed all the time, but I like to be able to experience more fully the surroundings, the plot elements, and the characters' personalities than Dark Mirror allowed me. 
 One thing that I was impressed by was the setting: not one, but two historical settings were involved, 1803 and WWII. M.J. Putney demonstrates a great amount of knowledge of the eras, though I would've preferred had she not stated this knowledge so matter of factly in the novel. If she had interwoven the historical information more seamlessly into the plot (something that Rick Yancey, author of The Monstrumologist Series, does very well), then I would've been truly impressed.