I have just finished reading this book by Charles D Hamilton and I have to say I was very impressed. This book covers the years from spartas victory in the Peloponnesian war in 404 BC to the end of the Corinthian war in 387/6 BC. The book primary covers the politics and diplomacy (hence the title) of and between the states of Sparta, Athens, Thebes, Corinth and to a lesser extent Argos.
I have read the authors book Agesilaus and the failure of spartan hegemony. On the strength of that book (highly recommended) I thought I would give this one a go and I was not disappointed. It was a highly detailed book that still has that entertaining style that made it a delight to read. Hamilton has thoroughly analysed the ancient sources and the modern sources to give a detailed balanced view of these years. He writes what each states desires and fears were and how they went about achieving there goals. The only minor point is that the battles themselves are not covered in great detail but as the title of the book shows this is about the politics and diplomacy. You will not read a better book on the Corinthian war. This is highly recommended. Also check out his other great book, Agesilaus and the failure of spartan hegemony.