The course is composed by two parts. The first one is addressed to the main principals of the tax law, arising both from the Constitution and from the sources of European Law. Moreover, the first part of the course will focus on the general discipline of tax obligations enforcement, on the taxable entities and the other subjects who are involved by the law in the tax obligation fulfillment and who are concerned by a duty of cooperation with the tax Authorities (deepening the nature and the function of the tax declaration). Finally, the activities of tax Authorities to verify the regular execution of tax fulfillments and to prevent or contrast the connected breaches are treated, and the powers that are granted to the tax-payer to assert their rights. In the second part of the course is focused on the main taxes of the Italian legislation (Irpef, Ires, Irap and Iva), describing the conditions to qualify the status of taxable person and the rules of determination of the taxable base.