Vertical thinking is step-by-step, procedural, outcome-focused. It helps you get things done.Always asking, “What is the obvious next step?” vertical thinking leads to incremental evolution and refinement. It is a ratchet that maintains what you’ve accomplished, then “click,” gives you a little bit more. The Japanese call it kaizen, “continuous improvement.”Vertical knowledge is narrow and deep. Specialized. Expert. Orderly.Horizontal thinking is boundless and broad. It is a searchlight that spots anomalies in a sea of similarities. It is the network of intersections in a map of metaphors. It is a detective that solves puzzles by seeing patterns, connections and relationships.Intuitive and instinctive, horizontal thinking leads to innovations by asking, “What doesn’t belong, and why?” It is a magnet that pulls the needle from the haystack. Linguists call this the Aha! moment or the eureka moment, that common human experience of suddenly understanding a previously incomprehensible problem or concept.Horizontal knowledge knows a little bit about everything. It is chaotic, pattern-seeking, creative.Every healthy person thinks vertically and horizontally, though most of us tend to prefer one or the other.The most effective partnerships have one partner who prefers to think vertically and another who prefers to think horizontally. These partners are the makers of miracles when they’re not driving each other crazy.Do you have a strong preference for one type of thinking? The first major milestone on your journey to success will be to find a partner who is your opposite. A person who brings the Willy to your Wonka.But that’s the easy part. That hard part is to respect that person’s opinion and take action on it, even when your instinct is to dismiss it out-of-hand as “irrelevant.”Chances are, you’ve got that person in your life already. Probably more than one. So here’s a suggestion: the next time they offer an opinion, or a possible solution, look at it as a valuable gift that needs to be opened and examined.You’re going to be surprised at the difference it makes.Roy H. Williams