Until recently, the issue of tax-efficient investing has been largely overlooked by the mainstream literature. And simple heuristics to guide investors and their advisors are not always as obvious as they might initially seem. This monograph explores central issues surrounding the use of tax-deferred investment accounts as a means of accumulating wealth and presents a useful framework, grounded in basic time-value-of-money concepts, that can be readily implemented by investment professionals (U.S. as well as non-U.S. based) in various tax environments (current as well as those resulting from changes in the tax code).