This study resolves divergent prior findings relating book-tax differences to future earnings, determines whether prior literature has missed relationships between different types of book-tax differences and pre-tax and/or after-tax income, and investigates prior earnings as a factor contributing to the observed relationships. As past research has found that some firms have large book-tax differences over several years, this study separates these firms with large stable book-tax differences from others with large book-tax differences (non-stable) when investigating the link between large book-tax differences and future earnings. Finally, this study investigates whether the relationship between book-tax differences and future earnings reflects information about prior earnings and finds that prior earnings growth explains much of the lower persistence found for firms with large book-tax differences.