I will third 1632... though I just read it, so I hope you don't mind if I don't read it again
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One warning about 1632.. it works fine as a stand a lone novel... but there are have been a number of sequels, both novels and shorter fiction.... and the number is growing, practically on a daily basis. If you get hooked on the series, well... it could take a prominent place on your reading list for a while.
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Bill