Superhuman stories are about humans who get special abilities that are not normal. Maybe the new powers come from nature. Two examples of this type are Olaf Stapledon's novel "Odd John" and Theodore Sturgeon's "More Than Human". Sometimes scientists give people special powers on purpose. one example is A.E. van Vogt's novel "Slan". Frederik Pohl's novel "Man Plus" is another good example from this category. In that book, government scientists make a man into a powerful cyborg (part human, part machine).