Monday morning, 9:17 a.m. Your computer's downloads folder contains 34 receipt photos from last week's business trip, 5 PDF quotations from vendors, and a half-finished draft report all mixed together. You need to sort these files, organize the receipts in Excel, and complete the report. Your team leader wants to see the results by 2 p.m. You check the clock. Four hours left.

In this situation, what you do with Claude is not ask a question in a chat box. You open a folder and tell it what needs to be done.

"Sort the receipt photos in my downloads folder by date, extract the vendor names and amounts, and create an Excel file. Rename the 5 quotation PDFs to the format 'VendorName_Quotation_Date' and move them to a separate folder." Claude makes a plan, reads the files, sorts them, renames them, and creates the Excel file. You meanwhile refine the report draft. By 1:30 p.m., both tasks are complete.

This is Claude Cowork. A desktop AI agent released by Anthropic in January 2026,an automated program that receives instructions from humans and makes decisions to execute tasks on its own. It differs from the chat interface approach of getting one answer at a time. Cowork accesses your computer folders, reads and edits files and creates new ones, connects to external services, and handles multi-step tasks independently.

The core philosophy of this book, compressed into one sentence, is this: "Delegation, not conversation." When you define specifically what needs to be done, Claude decides how to do it and executes it on its own.

That said, this book is not for programmers or IT specialists. The primary readers are office workers, business owners, freelancers, government employees, and students with only basic computer skills,writing documents and sending emails. It is fine if you have never used an AI tool before. We start with installation.

This book covers eight areas of work. It begins with fundamental tasks like file organization and progresses through Excel data analysis, marketing content creation, web research, email and calendar management, HR and legal document review, software development assistance, and ends with combining multiple tools to create automated workflows. Each chapter starts with following a single simple task, then varies the conditions, and finally combines multiple features in real-world business scenarios.

Every practice example includes prompts you can copy and paste directly. Rather than vague guidance like "try doing it this way," I designed them so that entering the completed sentence produces results. I also compare effective and ineffective prompts side by side. When you see the difference firsthand, the sense of how to write good instructions takes hold quickly.

One thing I should mention upfront. As of 2026, Cowork is evolving rapidly. Starting as a macOS research preview in January, plugins and connectors have been added, Windows support has arrived, and features enabling direct operation within Excel and PowerPoint have emerged. The screens and menu locations in this book may differ from what you actually see. When that happens, please check the official Anthropic documentation at support.claude.com. This book is not a collection of screenshots from a particular version, but rather a guide to the mindset of using Cowork and the practice of delegation. Even as versions change, those principles remain constant.

Now we begin. In Chapter 1, from installing Cowork to opening a folder and issuing your first task takes around 10 minutes. After those 10 minutes, you will experience for the first time handing work to an AI agent. That experience will change your Tuesday afternoon.

Author: Kim Kyung-jin