Volume 15 of 20 · PDF edition

In progress

Retrieval, Knowledge, and Memory

For teams building grounded, updateable, personalized systems with retrieval, editing, memory, continual learning, and unlearning.

Read every available chapter online for free. The paid edition is a focused, carefully typeset volume PDF with future chapters, updates, and errata included.

Written chapters
19 written chapters
Planned chapters
6 planned chapters
Approximate pages
~600 pages
Price
$24 one-time
Language AI Handbook, Volume 15: Retrieval, Knowledge, and Memory cover

Author and edition details

About the author and Volume 15 PDF edition

Michael Brenndoerfer, author of Language AI Handbook

Michael Brenndoerfer

Michael has spent more than a decade working across software engineering, data, AI, and business. He writes to understand difficult ideas more deeply and to share what he learns in a clear, practical way.

Edition
Volume 15 PDF 2026.08.0
Published
Last reviewed

Focused learning path

What this volume covers

  • Retrieval-Augmented Generation
  • Knowledge, Memory, Editing, and Unlearning
  • Continual Learning

Audience and prerequisites

Where this volume fits

For teams building grounded, updateable, personalized systems with retrieval, editing, memory, continual learning, and unlearning.

Prerequisites: Assumes embeddings from Volume 2 and model fundamentals from Volumes 8–9.

Free online preview

Start with “RAG Motivation: Solving Hallucinations & Knowledge Gaps

Discover why LLMs need Retrieval-Augmented Generation. Learn how RAG bridges knowledge gaps, reduces hallucinations, and enables non-parametric memory.

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Exact contents

19 chapters available now

The current PDF contains every linked chapter below. The remaining 6 planned chapters will be added through free volume updates.

Part XLIV: Retrieval-Augmented Generation

  1. 01
    RAG Motivation: Solving Hallucinations & Knowledge Gaps

    Discover why LLMs need Retrieval-Augmented Generation. Learn how RAG bridges knowledge gaps, reduces hallucinations, and enables non-parametric memory.

  2. 02
    RAG Architecture: Components, Timing & Design Patterns

    Master RAG system design by exploring retriever-generator interactions, timing strategies like iterative retrieval, and architectural variations like RETRO.

  3. 03
    Dense Retrieval: Semantic Search & Bi-Encoder Implementation

    Master dense retrieval for semantic search. Explore bi-encoder architectures, embedding metrics, and contrastive learning to overcome keyword limitations.

  4. 04
    Contrastive Learning for Retrieval: InfoNCE & DPR Guide

    Master contrastive learning for dense retrieval. Learn to train models using InfoNCE loss, in-batch negatives, and hard negative mining strategies effectively.

  5. 05
    Document Chunking: Optimizing RAG Retrieval Pipelines

    Master document chunking for RAG systems. Explore fixed-size, recursive, and semantic strategies to balance retrieval precision with context window limits.

  6. 06
    Embedding Models: Architecture, Pooling & Selection

    Learn how embedding models convert text to vectors for RAG. Covers bi-encoder architecture, pooling strategies, dimensionality trade-offs, and model selection.

  7. 07
    Vector Similarity Search: Metrics & Approximate Methods

    Explore vector similarity search for RAG systems. Compare cosine, dot product, and Euclidean metrics, and implement exact vs. approximate search with FAISS.

  8. 08
    HNSW Index: Architecture for Fast Vector Search

    Master Hierarchical Navigable Small World (HNSW) graphs for vector search. Learn graph architecture, construction, and tuning for high-speed retrieval.

  9. 09
    IVF Index: Clustering-Based Vector Search & Partitioning

    Master IVF indexes for scalable vector search. Learn clustering-based partitioning, nprobe tuning, and IVF-PQ compression for billion-scale retrieval.

  10. 10
    Product Quantization: Vector Compression for ANN Search

    Learn how Product Quantization compresses embeddings up to 100x using learned codebooks and asymmetric distance computation for scalable vector search.

  11. 11
    Hybrid Search: BM25 and Dense Retrieval Combined

    Learn how hybrid search fuses BM25 keyword retrieval with dense vector retrieval using reciprocal rank fusion and weighted score combination to improve recall.

  12. 12
    Reranking: Cross-Encoders for Precise Information Retrieval

    Learn how reranking with cross-encoders solves bi-encoder limitations. Master two-stage retrieval, training strategies, and latency optimization for production search systems.

  13. 13
    RAG Prompt Engineering: Context Placement & Citation Strategies

    Master RAG prompt engineering with strategic context placement, citation formats, and truncation strategies to improve LLM accuracy and reduce hallucinations.

  14. 14
    RAG Evaluation: Metrics for Retrieval and Generation Quality

    Master RAG evaluation with metrics for retrieval quality (Precision@K, NDCG, MRR) and generation faithfulness using the RAGAS framework for AI systems.

Part XLV: Knowledge, Memory, Editing, and Unlearning

  1. 01
    Parametric and External KnowledgePlanned

    What models store, what retrieval stores, and how to choose among prompting, RAG, editing, and retraining.

  2. 02
    Knowledge EditingPlanned

    Localized weight updates, memory-based editors, specificity, generalization, and multi-hop consistency.

  3. 03
    Knowledge Freshness and Temporal UpdatesPlanned

    Time-sensitive facts, temporal benchmarks, update propagation, versioning, and rollback.

  4. 04
    Personalization and Long-Term MemoryPlanned

    User models, episodic and semantic memory, consent, retention, conflict resolution, and forgetting.

  5. 05
    Machine UnlearningPlanned

    Forget sets, retraining baselines, approximate removal, privacy goals, and the limits of verification.

  6. 06
    Evaluating Knowledge InterventionsPlanned

    Efficacy, locality, generalization, side effects, privacy leakage, and auditable change histories.

Part XLVI: Continual Learning

  1. 01
    Continual Learning Problem

    Covers continual learning definition, catastrophic forgetting, continual learning scenarios.

  2. 02
    Regularization Methods

    Covers elastic weight consolidation, synaptic intelligence, parameter importance, regularization trade-offs.

  3. 03
    Replay Methods

    Covers replay buffer design, pseudo-rehearsal, generative replay, replay selection.

  4. 04
    Architecture Methods

    Covers progressive networks, expert expansion, architecture search, modular approaches.

  5. 05
    Continual Learning Evaluation

    Covers forward transfer, backward transfer, evaluation protocols, continual benchmarks.

Volume 15 PDF

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Edition 2026.08.0

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