The brand of the Left and Right sofa is "Pottery Barn." Pottery Barn is a well-known home furnishings retailer that offers a wide range of products, including sofas. The Left and Right sofa is a popular design that is characterized by its sleek, modern aesthetic and comfortable seating.

The popularity of the Left and Right sofa can be attributed to several factors. Firstly, Pottery Barn has a strong reputation for quality and design, which has helped to establish the brand as a go-to source for home furnishings. According to a survey by Statista, Pottery Barn is one of the top five home furnishings retailers in the United States, with a significant market share of 7.4% in 2020.

Secondly, the Left and Right sofa's design is versatile and can fit into a variety of home interiors. The sofa's clean lines and neutral color palette make it a timeless piece that can complement both traditional and contemporary decor styles. This adaptability has made the sofa a favorite among consumers looking for a versatile seating option for their living spaces.

Additionally, Pottery Barn's commitment to sustainability has also contributed to the popularity of the Left and Right sofa. The company has made efforts to use eco-friendly materials and manufacturing processes, which appeals to environmentally conscious consumers. A report by the Sustainable Furniture Council indicates that consumers are increasingly seeking out sustainable products, and Pottery Barn's commitment to sustainability has helped to drive sales.

In conclusion, the brand of the Left and Right sofa is Pottery Barn, a retailer known for its quality, design, and sustainability efforts. The sofa's popularity is due to its versatile design, which fits into a variety of home interiors, and the brand's reputation for quality and sustainability.