Robert E. May 
Union, the Confederacy, and the Atlantic Rim [PDF ebook] 

From French intervention in Mexico to British interests in the Caribbean, the impact of the Civil War extended far beyond military campaigns in Virginia, diffusing widely into the Atlantic world. Revised to take into account the outpouring of scholarship on Civil War diplomacy that has appeared since the book was first published, The Union, the Confederacy, and the Atlantic Rim features essays by acclaimed historians Howard Jones, R. J. M. Blackett, Thomas Schoonover, and James M. Mc Pherson.