This is a new printing of the classic book by Dickson. It was to meet the numerous needs of the student in regard to his earlier and future mathematical courses that the present book was planned with great care and after wide consultation. It differs essentially from the author's "Elementary Theory of Equations", both in regard to omissions and additions, and since it is addressed to younger students and may be used parallel with a course in differential calculus. Simpler and more detailed proofs are now employed. The exercises are simpler, more numerous, of greater variety, and involve more practical applications. There are more than 480 exercises for students to practice. Topics covered include complex numbers, roots of equations, the quadratic equation, graphical methods, cubic and quartic equations, numerical methods, systems of linear equations, etc. Answers to all the exercises are provided at the end of the book. This is a new, high quality, and affordable edition.