Concepts
Deep-dive explanations of the core ideas behind the Galen API. Not reference docs — conceptual understanding.
Knowledge Graph
How Galen's 280K-entity cancer knowledge graph is structured — entity types, relationship types, provenance, and traversal patterns.
Pearl Causal Hierarchy
Judea Pearl's three-layer causal framework (L1 association, L2 intervention, L3 counterfactual) and how Galen implements it for drug discovery.
Evidence Quality
How evidence_quality ratings work, what grounded_sources means, and how to interpret L2/L3 confidence scores in API responses.
Data Sources
The 28 integrated biomedical databases — what each one contributes to the knowledge graph, update frequency, and provenance tracking.