This book is a handbook on topics in High School Algebra. We have covered the topics like - Ratio, Proportion, Variation, Progressions, Surds, Imaginary Quantities, Quadratics, Permutations, Combinations, Mathematical Induction, Binomial Theorem, Logarithms, Inequalities, Probabilities and Determinants. Each chapter is follows a simple structure. A definition of terms and detailed explanation of concepts; followed by derivation of useful formulas through first principles. A few problems are solved in order to give a flavor of the problem solving process. This book is intended to help the student to understand ways to build an airtight reasoning on how the problem solving process moves towards the final answer. This serves as a demonstration of our understanding of the subject - basics, formulas and methods of manipulation. Students interested in solving additional problems may refer to the books "Problems in High School Algebra" and "Challenges in High School Algebra".