OpenAI's Deep Research is an advanced AI model designed to autonomously conduct complex research tasks by browsing the web, analyzing data, and producing detailed, citation-rich reports in a fraction of the time it would take human researchers. Built on OpenAI's o3 reasoning model, this agentic AI distinguishes itself from traditional chatbots by planning research strategies, refining queries, and conducting iterative searches to gather and synthesize information without human intervention after the initial prompt. Deep Research follows a five-phase process, including task clarification, query decomposition, iterative searching, content analysis across diverse formats, and report synthesis, all underpinned by a ReAct-style plan-act-observe loop. It effectively handles extensive reasoning chains, backtracks from unproductive paths, and uses integrated tools like web browsing and code interpretation to enhance its research capabilities. The model's outputs have been favorably compared to professional analyst work, demonstrating its potential to revolutionize knowledge work by automating complex research tasks across various domains.