The present book for Class XI Mathematics contains different types of questions of varying difficulty levels. Also, a detailed explanation for comprehensive understanding has been given for all objective and subjective problems. Some questions covered in the book would require the students to apply simultaneous understanding of more than one chapter/unit. The book has been divided into 16 chapters namely Sets, Relations & Functions, Trigonometric Functions, Principle of Mathematical Induction, Complex Numbers & Quadratic Equations, Linear Inequalities, Permutations & Combinations, Binomial Theorem, Sequence & Series, Straight Lines, Conic Sections, Introduction of Three Dimensional Geometry, Limits & Derivatives, Mathematical Reasoning, Statistics, and Probability. The problems covered in the book will encourage teachers to design quality questions on their own. The questions provided in the book will test comprehension, information recall, analytical thinking and problem-solving ability, creativity, and speculative ability. The book will also be highly useful for school examinations and to build a foundation for entrance examinations.