8/12/2025

A Step-by-Step Guide to Feeding a Large Book to a Local LLM with Ollama

Hey there! So, you've got a massive book—maybe a dense technical manual, a sprawling novel, or a collection of research papers—& you're thinking, "how cool would it be if I could just talk to this thing?" Turns out, you absolutely can. We're going to walk through how to feed a large book, or any big document for that matter, to a local Large Language Model (LLM) using a fantastic tool called Ollama.
This isn't just a gimmick. It's about creating a personal, private knowledge base that you can query in natural language. Think about it: no more endless searching through PDFs, no more trying to remember which chapter had that one specific piece of information. Just you, your documents, & an AI that knows them inside & out. And because we're doing it locally, your data stays YOUR data. Pretty cool, right?
We're going to get into the nitty-gritty of it, from setting up your environment to the "magic" of Retrieval-Augmented Generation (RAG), which is the core technique we'll be using. This guide is for anyone who's a little bit curious & not afraid to get their hands dirty with some code. Let's dive in.

The Big Picture: How Does This Even Work?

Before we start installing stuff, let's get a handle on what we're actually building. You can't just drop a 500-page PDF onto an LLM & expect it to work. Most LLMs have a "context window," a limit to how much text they can "remember" at one time. A whole book is WAY too big.
So, we have to be clever. This is where Retrieval-Augmented Generation (RAG) comes in. It's a fancy term for a pretty intuitive process. Here’s the breakdown:
  1. Ingestion & Chunking: First, we take our large book & break it down into smaller, manageable pieces, or "chunks." This is a crucial step, & how we do it can have a big impact on the quality of the answers we get.
  2. Embedding & Storing: Next, we convert each of these text chunks into a numerical representation called an "embedding." You can think of embeddings as a way of capturing the semantic meaning of the text in a way that a computer can understand. We then store all these embeddings in a special kind of database called a "vector database."
  3. Retrieval: Now, when you ask a question (or "query"), we first convert your question into an embedding as well. Then, we use the vector database to find the text chunks from the book that are most similar, or semantically relevant, to your question.
  4. Generation: Finally, we take the most relevant text chunks we found & "augment" the LLM's prompt with them. We essentially tell the LLM, "Here's the user's question, & here's some relevant context from the book. Now, answer the question based on this context."
This way, the LLM doesn't need to have the entire book in its memory. It just gets the most relevant snippets it needs to answer your specific question. It’s a powerful technique that lets us work with massive amounts of information, all on our local machine.

Step 1: Getting Your Local Environment Ready

Alright, let's start setting things up. We're going to need a few key pieces of software.

Installing Ollama

Ollama is the star of the show here. It's a fantastic tool that makes it incredibly easy to download & run powerful open-source LLMs right on your own computer.
  1. Download & Install: Head over to the Ollama website & grab the installer for your operating system (macOS, Linux, or Windows).
  2. Pull the Models: Once Ollama is installed, you'll need to download the models we'll be using. We need two types of models:
    • A chat model for the generation part. A great one to start with is
      1 llama3
      .
    • An embedding model to create the numerical representations of our text.
      1 nomic-embed-text
      is a solid choice.
    You can download these by opening your terminal & running the following commands:

Copyright © Arsturn 2025