There are plenty of reasons for which tax rights arc changed. One of the reason is change in extent of political and economical system in the country. According to every very new decree taxation is being changed and adapted lo be consistent with political and economical policy which forces different rules in tax policy. However either current political system or economical one is stable they both are often said to be improved what is usually joined with necessity of changing taxation. The income tax act passed in July 26th 1991 has forced lor 12 years and it’s obligation is to make taxation changes approved in 2004 understandable and comprehensible from the national budget and taxpayers point of view. Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 zostało dofinansowane ze środków MNiSW w ramach działalności upowszechniającej naukę.