Baruch Spinoza was a 17th-century Dutch philosopher who profoundly influenced modern Western philosophy. He is best known for his work "Ethics," in which he presented a rationalist and monist worldview, arguing that God and Nature are one and the same, and that everything in the universe is determined by natural laws. Spinoza's radical ideas challenged traditional religious and philosophical concepts, leading to his excommunication from the Jewish community and the banning of his works, but his thoughts later gained recognition and continue to be influential in philosophy today.