The Other Teddy Roosevelts — Mike Resnick

Theodore Roosevelt: president, naturalist, explorer, author, cowboy, police commissioner, deputy marshal, soldier, taxidermist, ornithologist, and boxer. Everyone knows about that.
But how about vampire hunter?
Or African king?
Or Jack the Ripper's nemesis?
Or World War I doughboy?
Mike Resnick (the most-awarded short story writer in science fiction history, according to Locus) has been the biographer of these other Teddy Roosevelts for almost two decades. Here you will find a familiar Roosevelt, but in unfamiliar surroundings stalking a vampire through the streets of New York, or a crazed killer down the back alleys of Whitechapel, coming face-to-face with the devastation of 20th Century warfare, waging an early battle for women's suffrage, applying all his skills to bring American democracy to the untamed African wilderness, or coming face-to-face with one of H. G. Wells' Martian invaders in the swamps of Cuba.
And, as Winston Churchill said of the Arthurian legends, if these stories aren't true, then they should have been.
Enjoy.