## TL;DR
Productivity systems organize tasks and time for maximum effectiveness. GTD (Getting Things Done, David Allen): capture everything → clarify → organize → review → engage. Pomodoro Technique (Cirillo): 25-min focused work + 5-min break. Eisenhower Matrix: urgent/important quadrants. Time blocking: schedule specific tasks in calendar.
## Core Explanation
GTD: externalize all commitments to trusted system, reduce cognitive load. Two-minute rule: if task takes <2 minutes, do it now. Weekly review: process inbox, update projects, plan next week. Deep work (Cal Newport): distraction-free concentration on cognitively demanding tasks. Parkinson's Law: work expands to fill available time. 'Eat the frog' (Brian Tracy): do hardest task first.
## Further Reading
- [Getting Things Done (David Allen)](https://gettingthingsdone.com/)