Graph Models Are Extremely Useful For A Large Number Of Applications As They Play An Important Role As Structuring Tools. They Allow To Model Net Structures - Like Roads, Computers, Telephones, Social Networks - Instances Of Abstract Data Structures - Like Lists, Stacks, Trees - And Functional Or Object Oriented Programming. The Focus Of This Highly Self-contained Book Is On Homomorphisms And Endomorphisms, Matrices And Eigenvalues.