Sloane opens by distinguishing lateral thinking — deliberately generating unconventional, indirect approaches to a problem — from more conventional vertical, linear problem-solving, arguing leaders specifically need lateral thinking skills to address genuinely novel challenges that established approaches can't adequately solve.

Core distinction he establishes:

• Vertical thinking follows logical, step-by-step reasoning from established premises, which works well for familiar problems but tends to reproduce familiar, incremental solutions rather than genuine breakthroughs
• Lateral thinking deliberately seeks out unconventional starting points and approaches, tolerating temporary illogic or provocation in service of eventually reaching genuinely novel solutions
• Sloane argues leaders specifically need to cultivate this skill, since many of the most significant business challenges require breaking from established patterns rather than simply optimizing them further

This opening distinction sets up the book's practical techniques for deliberately cultivating lateral thinking, covered throughout the rest of the book.