Generate a full detail guide on the practice of companion planting. The guide must be a practical reference tool. It should include: 1. A simple explanation of the science and theory behind companion planting. 2. A detailed chart of common vegetables and their beneficial and detrimental companions. 3. A deep dive into the 'Three Sisters' planting method as a classic example. 4. A list of specific flowers to plant throughout a vegetable garden to attract pollinators and deter pests. Please include a supportive disclaimer.