S.L. Loney was a prominent Indian mathematician and author, best known for his contributions to mathematics education. He was born in 1860 and became widely recognized for his textbooks, particularly in the fields of geometry and algebra. His works have been used by students and educators for generations, making complex concepts more accessible. Loney's most famous book, Plane Trigonometry, is still referenced today for its clear explanations and practical approach. He also wrote on Coordinate Geometry and Higher Algebra, helping to shape the curriculum in Indian schools and colleges. His legacy continues to influence mathematics teaching in India.