"Elasticsearch ELSER: Semantic Search Without Managing Embeddings" Semantic search is often introduced as a relevance breakthrough but implemented as an operational burden. This book is for experienced Elasticsearch engineers, search architects, and platform teams who want the gains of semantic retrieval without inheriting the complexity of external embedding pipelines, vector infrastructure, and custom orchestration. It shows how ELSER changes that equation by bringing search-native semantic capabilities directly into Elasticsearch. Across the book, readers learn how ELSER’s sparse retrieval model works, why the `semantic_text` workflow is now the preferred implementation path, and how inference endpoints, indexing flows, query behavior, and reindexing fit into a production-grade architecture. The coverage goes well beyond setup: it explains version milestones, ELSER v2 compatibility boundaries, default endpoint changes, hybrid BM25-plus-semantic retrieval design, relevance evaluation, and the infrastructure decisions that shape performance, scale, and operational stability. Rather than treating semantic search as a black box, the book equips advanced practitioners to make precise architectural choices. It emphasizes trade-offs, lifecycle management, and production hardening, making it especially valuable for teams modernizing existing Elasticsearch systems while preserving rigor, control, and predictable search behavior.