After all the festivities, laughter, and gift giving for this holidays, giggles and grins quickly meld into groans and glowers as Income tax Preparation Season rears its ugly features. From January 15th until April 15th, Americans fuss and fume about our rising income taxes. Nevertheless, in an odd sort of way, some must love the gloom since they'll file for an extension, prolonging the agony of the inevitable. You need to understand the technique of marginal tax rate. That is the very powerf...