BASIC CONCEPTS Algebras Examples Subalgebras Congruence Relations and Quotients Exercises GALOIS CONNECTIONS AND CLOSURES Closure Operators Galois Connections Concept Analysis Exercises HOMOMORPHISMS AND ISOMORPHISMS The Homomorphism Theorem The Isomorphism Theorems Exercises DIRECT AND SUBDIRECT PRODUCTS Direct Products Subdirect Products Exercises TERMS, TREES, AND POLYNOMIALS Terms and Trees Term Operations Polynomials and Polynomial Operations Exercises IDENTITIES AND VARIETIES The Galois-Connection (Id, Mod) Fully Invariant Congruence Relations The Algebraic Consequence Relation Relatively Free Algebras Varieties The Lattice of All Varieties Finite Axiomatizability Exercises TERM REWRITING SYSTEMS Confluence Reduction Systems Term Rewriting Termination of Term Rewriting Systems Exercises ALGEBRAIC MACHINES Regular Languages Finite Automata Algebraic Operations on Finite Automata Tree-Recognizers Regular Tree Grammars Operations on Tree Languages Minimal Tree-Recognizers Tree Transducers Turing Machines Undecidable Problems Exercises MAL''CEV-TYPE CONDITIONS Congruence Permutability Congruence Distributivity Arithmetical Varieties n-Modularity and n-Permutability Congruence Regular Varieties Two-Element Algebras Exercises CLONES AND COMPLETENESS Clones as Algebraic Structures Operations and Relations The Lattice of all Boolean Clones The Functional Completeness Problem Primal Algebras Different Generalizations of Primality Preprimal Algebras TAME CONGRUENCE THEORY Minimal Algebras Tame Congruence Relations Permutation Algebras The Types of Minimal Algebras Mal''cev Conditions and Omitting Types Residually Small Varieties TERM CONDITION AND COMMUTATOR The Term Condition The Commutator COMPLETE SUBLATTICES Conjugate Pairs of Closure Operators Galois-Closed Subrelations Closure Operators on Complete Lattices G-CLONES AND M-SOLID VARIETIES G-Clones H-Clones M-Solid Varieties Intervals in the Lattice L(t) HYPERSUBSTITUTIONS AND MACHINES The Hyperunification Problem Hyper-Tree-Recognizers Tree Transformations BIBLIOGRAPHY INDEXREWRITING SYSTEMS Confluence Reduction Systems Term Rewriting Termination of Term Rewriting Systems Exercises ALGEBRAIC MACHINES Regular Languages Finite Automata Algebraic Operations on Finite Automata Tree-Recognizers Regular Tree Grammars Operations on Tree Languages Minimal Tree-Recognizers Tree Transducers Turing Machines Undecidable Problems Exercises MAL''CEV-TYPE CONDITIONS Congruence Permutability Congruence Distributivity Arithmetical Varieties n-Modularity and n-Permutability Congruence Regular Varieties Two-Element Algebras Exercises CLONES AND COMPLETENESS Clones as Algebraic Structures Operations and Relations The Lattice of all Boolean Clones The Functional Completeness Problem Primal Algebras Different Generalizations of Primality Preprimal Algebras TAME CONGRUENCE THEORY Minimal Algebras Tame Congruence Relations Permutation Algebras The Types of Minimal Algebras Mal''cev Conditions and Omitting Types Residually Small Varieties TERM CONDITION AND COMMUTATOR The Term Condition The Commutator COMPLETE SUBLATTICES Conjugate Pairs of Closure Operators Galois-Closed Subrelations Closure Operators on Complete Lattices G-CLONES AND M-SOLID VARIETIES G-Clones H-Clones M-Solid Varieties Intervals in the Lattice L(t) HYPERSUBSTITUTIONS AND MACHINES The Hyperunification Problem Hyper-Tree-Recognizers Tree Transformations BIBLIOGRAPHY INDEXas Different Generalizations of Primality Preprimal Algebras TAME CONGRUENCE THEORY Minimal Algebras Tame Congruence Relations Permutation Algebras The Types of Minimal Algebras Mal''cev Conditions and Omitting Types Residually Small Varieties TERM CONDITION AND COMMUTATOR The Term Condition The Commutator COMPLETE SUBLATTICES Conjugate Pairs of Closure Operators Galois-Closed Subrelations Closure Operators on Complete Lattices G-CLONES AND M-SOLID VARIETIES G-Clones H-Clones M-Solid Varieties Intervals in the Lattice L(t) HYPERSUBSTITUTIONS AND MACHINES The Hyperunification Problem Hyper-Tree-Recognizers Tree Transformations BIBLIOGRAPHY INDEX.