An approach to the planning, design, creation, implementation and
evaluation of effective instruction.

The fundamental idea:
Empirically based principles can be applied to create effective instruction.

Its history is:	Its history is NOT:
A gradual confluence of ideas	A linear progression
	A tracing of events

t i m e l i n e
Pre-20s | 20s | 30s | 40s | 50s | 60s | 70s | 80s | 90s and beyond