This Key represents the uses of limitation. It shows that the dance of life is carried on by means of the form-building, solidifying power that gives us definiteness. It is that power which enables us to measure and to know with exactness and precision. The influence of Saturn is always limiting and restrictive, but this is never malefic unless we allow it to use us instead of our using it. This power is the very basis upon which all science is founded. In token of the correct way to use this force of limitation, the mode of consciousness attributed to Key 21 is the Administrative Intelligence. The result of such right use is evident in that this Key also represents the stage of spiritual unfoldment called Cosmic Consciousness. Remember, too, that concentration is an act of limitation.
The four figures in the corners are the same as in Key 10. Another hint of relationship between these two keys is the veil that covers the central figure. This is in the form of the letter Kaph, which is the letter attributed to the 10th Key. The wreath is a mathematical symbol, but among other things it refers to the Life-Power as the fundamental principle of form. Since a wreath is a work of man it refers to man's use of this power for building. The central figure appears to be feminine, but the legs have a masculine appearance which reveals that the figure is really androgynous. The spirals in her hands represent integration and disintegration, since they are turning in opposite directions.
Apparently this Key is the end of the series, but there is no end to it in reality. 21 is a triple manifestation of the number 7, and 7 represents the end of a cycle and the beginning of the next. Key 0 follows Key 21. Thus the never ceasing law of cyclicity is manifest in the symbolism of the TAROT. There are always other steps to take, always a higher goal to strive for. As you continue in your search for Truth in your ever increasing spiritual growth you will find the principles embodied in the TAROT will be those upon which you must rely for your guidance in every plane of existence, for all evolution is the manifestation and expression of Cosmic Law.