This book provides insights into tax compliance among Congolese taxpayers at the Matadi tax center. The study is based on the following hypotheses: (1) taxpayers at the Matadi tax center have a low level of tax civic-mindedness; (2) the interaction of three rationalities (utilitarian, axiological and cognitive) in the tax return decision is the reason for the deviant tax behavior of taxpayers at the Matadi tax center; and (3) taxpayers at the Matadi tax center have a negative attitude toward the tax law.The results obtained allowed us to confirm our first two hypotheses and to refute the third hypothesis. The subjects of the study have an overall positive attitude towards tax law and, on the other hand, show deviant tax behavior. Thus, public education and awareness campaigns on accurate tax reporting are necessary to move from deviant to legal tax behavior.