From a multi-study Bain & Company search to identify the most reliable principles on which to base a strategy for profitable growth, two key insights emerged. The first is that the most promising growth opportunities tend to lie adjacent to the core business. Indeed, the farther away from the core business companies extend themselves in pursuit of growth, the worse they tend to dare. The second insight, and the one focused on here, is that the competitive strength of the core business itself is a crucial factor in the success of growth initiatives. The principle message of this article is that companies should first re-examine the strength of their core business before they attempt to expand beyond it. Even if the core business is a market leader, it may need to seek even greater competitive advantage before essaying major growth initiatives. If it's well behind the market leaders, its position can be greatly strengthened through consolidation, upwards or downwards. The result will be a sounder, more reliable base for growth. The cases featured here help show the way.