Henry George 
Protection or Free Trade [PDF ebook] 
An Examination of the Tariff Question, With Especial Regard to the Interests of Labour

In this book, first published in 1890, the author endeavours to determine whether protectionism or free trade better accords with the interests of labour – particularly with regards to the raising of wages. He analyses the popularity of protection in the face of the evidence of its fallacies, and examines the principle of free trade and its consequences.