Vitamin E has been a generic term for all tocopherol and tocotrienol derivatives. The most active form of vitamin E isoforms in vivo is regarded to be $alpha$-tocopherol which is the only form defined as vitamin E in the US Food and Nutrition Board, causing controversy over setting dietary reference intake (DRI) of vitamin E. However, most of the countries other than the US maintain the original concept that all isoforms are accepted as vitamin E but with different biopotency. The roles of the isoforms of vitamin E other than $alpha$-tocopherol have received continuous attention. Among them those of $gamma$-tocopherol and $alpha$-tocotrienol have been most studied in comparison with $alpha$-tocopherol, since $gamma$-tocopherol comprises major form of vitamin E in many plant seeds and those of the both vitamin E have been implicated in unique physiological functions. This review summarizes findings that have led a better understanding of vitamin E absorption, transport, tissue storage and various functions common and specific to vitamin E isoforms focusing $alpha$- and $gamma$-tocopherol as well as tocotrienols. It is expected to help redefining vitamin E and setting its DRI for Koreans.