## TL;DR

Design thinking is a human-centered problem-solving methodology popularized by IDEO. Five phases: Empathize (understand users), Define (frame problem), Ideate (brainstorm solutions), Prototype (build low-fidelity versions), Test (gather feedback). Iterative, not linear — you can move back and forth.

## Core Explanation

Empathy: observe, interview, immerse in user experience. Define: synthesize insights into problem statement. Ideate: quantity over quality, defer judgment, 'yes, and...' thinking. Prototype: fail fast, learn faster — paper sketches, wireframes, role-play. Test: real users, real feedback, iterate. Divergent thinking → Convergent thinking. Double Diamond model (Design Council) formalizes the process. Applications beyond products: services, organizations, social innovation.

## Further Reading

- [Change by Design (Tim Brown)](https://www.harpercollins.com/products/change-by-design-tim-brown)