Article 44 establishes the fundamental principle for tax deduction, allowing a Taxable Person to deduct the value of Deductible Tax from the Tax Due and Payable within the same Member State. This right is contingent upon the tax being incurred in the course of making Taxable Supplies. The entitlement to deduct arises at the moment the Deductible Tax becomes due. A specific provision allows a customer liable for tax under the reverse charge mechanism to deduct the related tax, provided they have declared the Tax Due as required under Article 41(2). Each Member State retains the authority to determine the detailed terms and provisions governing tax deduction.