Napoleon Hill opens Think and Grow Rich! with his foundational premise, distilled from over two decades of research into hundreds of successful individuals: definite, focused thought, combined with burning desire, is the actual starting point of all genuine achievement and wealth accumulation.

Hill's foundational claim:

• He argues that success and failure alike begin as thought patterns before manifesting as circumstances, positioning mindset as the causal starting point rather than a byproduct of external circumstances
• This research, commissioned originally by Andrew Carnegie, involved extensive interviews with hundreds of America's most successful individuals during the early twentieth century, from which Hill claims to have extracted common underlying principles
• The book's title itself reflects this core thesis — that genuine wealth-building begins in the mind, through deliberate thought and desire, before manifesting in external action and results

This opening framing sets up the book's overall structure: thirteen distinct principles, each addressed in a dedicated chapter, that Hill presents as the extracted common denominators of the successful individuals he studied.