This provides an introduction to string theory for undergraduates. The book assumes basic knowledge of classical mechanics, quantum mechanics and Special Relativity. This provides an excellent introduction to string theory in terms very simple terms. This is a suitable text for a 2/3 yr undergrad with no prior knowledge of quantum field theory.

This is one of the classic texts on this subject. It introduces both bosonic string theory and superstring theory. The book mostly uses light-cone quantization and Canonical quantization.

These are other classic texts on this subject. It mostly uses path integral quantization and hence provides a complementary picture of GSW.

This provides an introduction to the more recent developments in superstring theory