From the designer:
Band of Brothers was a pleasant surprise for me as I found my interest in the period became greater the longer I worked on this supplement. If one is looking for a variety of unit types, tactical doctrine, or weaponry, medieval/renaissance warfare has much to offer. If one wants colorful dress and dramatic costumes, then the Landtsknecht and the Ottoman Janissaries are but a few of the many available troops. Even more appealing is that this is a period of fascinating transitions in the practice of warfare.
Two of the greatest transitional effects are the introduction and growing effectiveness of gunpowder weapons, both in the form of artillery, as well as personal weapons, and the ability for nations to field semi-national armies. The creation of these larger forces and their supply was a necessary social foundation for the Military Revolution that allowed the great armies of the 17th century and later.
Expands:
Piquet: Master Rules for Wargaming