## TL;DR
Plate tectonics is the unifying theory of geology, explaining earthquakes, volcanoes, mountain building, and fossil distribution. Earth is unique in the solar system in having active plate tectonics.

## Core Explanation
Three boundary types: divergent (plates move apart — Mid-Atlantic Ridge), convergent (plates collide — Himalayas, Andes), transform (plates slide past — San Andreas Fault). Seafloor spreading at mid-ocean ridges is balanced by subduction at trenches.

## Detailed Analysis
The Wilson Cycle describes ocean basin lifecycle: rifting→spreading→subduction→collision (200-500 million years). Supercontinent cycle: Pangaea (335-175 Ma) preceded by Rodinia (1.3-0.75 Ga). Plate tectonics recycles crust and regulates climate over geological timescales.

## Further Reading
- USGS Earthquake Hazards Program
- NOAA Ocean Explorer: Plate Tectonics
- National Geographic: Plate Tectonics