Leonardo, as he is almost always called, was trained to be a painter. But he became one of the most versatile geniuses in history. His interests and achievements spread into an astonishing variety of fields that are usually consider scientific specialties. Leonardo studied anatomy, astronomy, botany, and geology, and he design machines and drew plans for hundreds of inventions.

Leonardo recorded his scientific observations and his ideas for inventions in notebooks. Many of the ideas and design Leonardo preserved in his notebooks were far ahead of their time. For example, he drew plans for a flying machine and parachute. Leonardo also stated that the sun does not move, through scientists of his day believed that the sun revolved around the earth. By the time Leonardo's scientific and technical investigation became widely known, other people had come up with many of the same ideas.

Although Leonardo explored an amazing number of areas of human knowledge, he was not a universal genius. For example, he had no interest in history, literature, or religion. He never developed his ideas systematically, and hi did not formulate scientific laws or principles. But Leonardo was an excellent observer. He concerned himself with what the eye could see, rather than with abstract thoughts.