Samuel Samuel & Co., Ltd. was one of the original companies that later formed Royal Dutch Shell. Founded by Jewish businessman Marcus Samuel in 1834, it first began as a small store named M. Samuel & Co., then commenced trading in East Asia from the mid-19^(th) century onwards, opened branch stores in Yokohama in 1876, engaged in oil trade in late 19^(th) century, and eventually became an international oil enterprise. Through maintaining good relations with the Japanese government, and exploiting the conflict between Western merchants and the Japanese government, Samuel Samuel & Co., Ltd. acquired the exclusive rights to supply raw opium for the monopolistic sale of the Office of the Governor-General, and sole distribution rights for crude camphor export, thus laying the foundation for its expansion in Taiwan. The Office of the Governor-General in turn relied on Samuel Samuel & Co., Ltd. to expand its oversea markets, while training local merchants to replace Samuel Samuel & Co., Ltd., and eventually forced it out of the Japanese market. However, Arai Taizi, who helped Samuel Samuel & Co., Ltd. acquire the exclusive rights to deal camphor, and comprador Wee Tong Bo both expanded their business substantially in Taiwan with the support of the company. This study traces the major stages of this influential yet little known company in Taiwan, who played a key role in the history of monopoly sale and industry during Japanese colonial era, portraying its trajectory in Taiwan, and thus investigating its connections with the industrial development of Taiwan.