Continuing on with the Florida theme from a couple of entries ago, in my opinion, the best single volume dealing with the Civil War period in the state is William N. Nulty's Confederate Florida : The Road to Olustee (1994: Univ. of Alabama Press). While the heart of the book is an excellent and detailed battle study of the Confederate victory at Olustee (aka Ocean Pond), military history is only a part of what makes Nulty's scholarship useful. Confederate Florida is also a well-researched general overview of the state's entry and service in the Confederacy, especially its vital role in keeping the Southern field armies supplied with beef.
For those readers more interested in Florida's Gulf Coast, George Buker's Blockaders, Refugees, and Contrabands : Civil War on Florida's Gulf Coast, 1861-1865 isn't definitive but is nevertheless a good place to start due to the broad range of subjects introduced.