The book Algebra provides a firm foundation in algebra for students at undergraduate and postgraduate level.Starting with an introduction to Elementary Number Theory, the text gives a streamlined account of Group Theory, Ring Theory and Field Theory. The discussion on elementary number theory serves as a gentle introduction to the art of writing proofs and abstraction. The approach to topics such as symmetric groups and dihedral groups will be novel to the undergraduate students. The topic on Group Action emphasizes geometric intuition and it plays an important role. The idea of factorization, a recurring theme in rings is emphasized and done in detail. Two outstanding results in Field Theory, namely Galois Theorem and Abel's Theorem are proved efficiently.The book contains a wealth of examples and exercises with varying level of difficulty-quite a few of them drawn from other branches of mathematics. The text emphasizes on concrete mathematics.