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Chapter 1: What Is a Search Engine, Really?

Understand the foundational responsibilities and evolving role of search engines in modern systems and AI applications.

Chapter Overview​

This chapter establishes the foundation for everything that follows. Before diving into data structures, distributed systems, or AI integration, you need to understand what a search engine actually does and how its role has evolved from simple keyword matching to powering contextual AI systems.

Search engines are no longer just tools for finding documents. They are retrieval systems that provide the essential context layer for AI inference, log analysis, e-commerce personalization, and countless other applications. Understanding this evolution is critical for designing systems that meet modern demands.

1.1.1 Grep

1.1.2 Retrieval engines

1.1.3 Retrieval vs. ranking vs. relevance

1.2 Anatomy of a Search Engine​

1.2.1 Ingestion and indexing

1.2.2 Querying and scoring

1.2.3 Ranking and relevance

1.3 Core Use Cases​

1.3.1 E-commerce, personalization, and filters

1.3.2 Logs, observability, and root cause detection

1.3.3 Legal, defense, and AI retrieval

Examples​

Examples coming soon.

Code examples for this chapter will demonstrate fundamental search concepts using Lucenia, including basic indexing, querying, and understanding how retrieval differs from simple pattern matching.