Johannes Gutenberg was a very clever man who lived a long time ago in Germany. He wanted to make books, but in those days, making books was very hard and expensive. People had to write everything by hand and it took a long time.
So, Gutenberg came up with a brilliant idea - he invented the "printing press". This was a machine that could print words onto paper really quickly and easily.
Gutenberg made his printing press by arranging small metal letters, called "type", onto a frame. Then, he inked the letters and pressed them down onto the paper. This made the words appear on the paper in a neat and tidy way.
Thanks to Gutenberg's amazing invention, he was able to make lots of books really quickly and cheaply. People loved his books and they started to read them more and more. This helped spread knowledge and ideas all over the world.
So, that's why Johannes Gutenberg is such an important person - he came up with a clever machine that changed the way we make and read books forever!