Structure of Decidable Locally Finite Varieties

0 Preliminaries.- 0.1 Languages, structures, algebras, and graphs.- 0.2 Decidability and interpretability.- 0.3 Varieties.- 0.4 Abelian and solvable algebras.- 0.5 Special kinds of varieties.- 0.6 Tame congruence theory.- 0.7 Definable relations in subdirect powers.- 1 Preview: The three sub varieties.- I: Structured Varieties.- 2: a property of the center.- 3: Centerless algebras.- 4: The discriminator subvariety.- 5: The Abelian subvariety.- 6: Transfer principles.- Summary of Part I.- II: Structured Abelian Varieties.- 7: Strongly solvable varieties.- 8: More transfer principles.- 9: Consequences of the transfer principles.- 10: Three interpretations.- 11: From strongly Abelian to essentially unary varieties.- 12: The unary case.- III: The Decomposition.- 13: The decomposition theorem.- 14: Conclusion.- Notation.