In the mathematical problem-solving literature, there are few works that focus on trigonometry and explore its vast applications. This book responds to the need of those who would like to expand their knowledge of trigonometry, to develop a solid understanding in trigonometry, and gain the necessary skills to solve trigonometry problems. The book presents complex trigonometric concepts in a simplified manner, making it suitable for both beginners and experienced problem solvers. It contains many examples and problems taken from various competitions and journals, helping readers to appreciate the relevance of trigonometry in today's mathematical contests. The book covers both the geometric and the algebraic aspects of trigonometry, providing a thorough understanding of basic trigonometric principles, identities, equations, and problem-solving techniques.