This is elementary book on determinants, matrices and linear transformation developed from scratch with a view to prepare the student to take up a course in linear algebra, and quantum mechanics.The point of view followed that the determinants and matrices are tools of mathematics designed for solving linear equations, rather than as a discovery - hence the name rediscover. Then matrix is shown as a independent entity for computation and lastly as a linear transformation or as an inner product space. The book is well readable in +2 lever and helpful in +3 level and in engineering. Selected problems for IITJEE are also included