The exponential growth in data generation has fundamentally transformed computational paradigms and analytical methodologies across diverse domains. This chapter provides a comprehensive examination of big data concepts, ecosystems, and data science methodologies that enable organisations to extract meaningful insights from vast, heterogeneous datasets. We explore technological foundations, including distributed computing frameworks, storage architectures, and analytical techniques, while addressing critical challenges related to privacy, scalability, and ethical considerations. Furthermore, we investigate emerging trends in artificial intelligence integration, edge computing, quantum computing applications, and sustainable data science practices.