I hope this is the right subreddit.
I'm a student of classics, so anything ancient (especially Greece/Alexander/Diadochi) would be excellent.
However, I'll devour pretty much anything: naval, siege, medieval, early modern, etc.
Not as good as the Mask of Command but you might enjoy Makers of Ancient Strategy a collection of essays edited by Victor Davis Hanson
Chapters
From Persia with Love
Propaganda and Imperial Overreach in the Greco-Persian Wars,Tom Holland
Pericles, Thucydides, and the Defense of Empire, Donald Kagan
Why Fortifications Endure
A Case Study of the Walls of Athens during the Classical Period,David L. Berkey
Epaminondas the Theban and the Doctrine of Preemptive War, Victor Davis Hanson
Alexander the Great, Nation Building, and the Creation and Maintenance of Empire , Ian Worthington
Urban Warfare in the Classical Greek World ,John W. I. Lee
Counterinsurgency and the Enemies of Rome, Susan Mattern
Slave Wars of Greece and Rome ,Barry Strauss
Julius Caesar and the General as State, Adrian Goldsworthy
Holding the Line ,Frontier Defense and the Later Roman Empire
This subreddit has a [book list] (http://www.reddit.com/r/AskHistorians/wiki/books), it's sorted by categories so you should be able to find something that takes your fancy.