Furthermore, the rules and principles that govern GAAP are sometimes different from those that govern income tax reporting. This is the primary reason that AFIT is a complex area of financial reporting. While for many transactions book and tax treatment are the same, often the treatment differs. These differences result in two different measures of income (book income and taxable income) as well as two different measures of assets, liabilities, and equity.13 These book-tax differences (BTDs) stem from tax legislation that mandates departures from GAAP accounting for various economic, social, political, and administrative reasons. There are two types of BTDs: temporary and permanent