The book provides a thorough, accessible, and current comprehension of Big Data for both business people and engineers. This book presents essential ideas, theories, terminology, and technologies related to Big Data. It also covers important analysis and analytics approaches. The information is rationally organized, given in clear and simple language, and backed with easily comprehensible examples. The objective of “Fundamentals of Data Science and Big Data Science” is to enhance decision-making by analyzing data. Currently, data science plays a crucial role in determining the advertisements that appear on the internet, the recommendations you get for books and films, the classification of emails into your spam folders, as well as the pricing of health insurance. This book provides a brief description of the developing discipline of data science, elucidating its progression, present applications, data infrastructure concerns, and legal issues. The text adopts a conversational tone and stays clear of complex mathematical ideas often associated with data science, instead focusing on straightforward explanations and real-world use cases. Upon concluding the book, readers will have acquired proficiency in controlling data, using data in the context of business challenges, and implementing optimal methodologies for data analysis. This book functions as a practical guide for Science/Engineering/MBA students, including both undergraduate and graduate students, who have an interest in the field of Data Science.