János Bolyai was a Hungarian mathematician born on December 15, 1802, in the city of Kolozsvár, which is now part of Romania. He is best known for his work in non-Euclidean geometry, a revolutionary concept that challenged the long-held beliefs of Euclidean geometry. Bolyai's groundbreaking ideas laid the foundation for modern geometry and influenced many future mathematicians. In 1823, Bolyai published a book titled "Appendix Scientiam Spatii Absolute," where he presented his theories on parallel lines and the nature of space. His work, although initially overlooked, eventually gained recognition and contributed significantly to the development of mathematics, particularly in the fields of geometry and topology.