Problems in Calculus of One Variablecovers the in-depth study of mathematical analysis based on many years of the author’s experience. The author has presented this book with an aim to train the students in an active approach to mathematical exercises, as is done at a seminar. The present book has been divided into eight chapters namely Introduction to Mathematical Analysis, Differentiation of Functions, Application of Differential Calculus to an investigation of Functions, Indefinite Integrals, Basic Method of Integration, Basic Classes of Integrable Functions, The Definite Integrals, Applications of the Definite Integral and Improper Integrals. Each chapter in the book begins with a theoretical introduction of the topics containing the principal definitions, theorems, and formulas followed by solved examples based on the topics discussed. The solved examples have been covered topic-wise along with the explanation of concepts for immediate and effective understanding of the concepts. The standard computational exercises are supplemented by examples and problems explaining the theory, promoting its deeper understanding and stimulating precise mathematical thinking. Some counter-examples explaining the need for certain conditions in the formulation of basic theorems are also included in the book. At the end of each chapter, unsolved practice exercises have been provided to help aspirants revise the concepts discussed in the chapter. At the end of the book, answers and solutions to the unsolved practice exercises have also been provided for better comprehension of the concepts. As the book contains relevant theoretical content along with an ample number of solved as well as unsolved problems covering the varied aspects of mathematical analysis, it for sure will help the students master their concepts of Problems in Calculus of One Variable.