Henry of Lancaster's Expedition to Aquitaine
>This reassessment of a neglected campaign draws on a wealth of original source material to furnish an examination of the campaign "in the round"; recruitment, preparations and financial administration, as well as its events and achievements, are examined closely. A detailed biographical study of the individuals who took up arms under Lancaster's command forms a main part of this work: the portrayal of hundreds of careers in arms allows us to glean a sense of what life was like for soldiers in this army and in the later Middle Ages in general. An investigation of the men's martial experience, motivations for service and personal military networks provides an understanding of how and, indeed, why the army was so effective in the field of war. It also reveals much about the emergence of professionalism in English medieval armies and offers a reassessment of Lancaster's importance as a captain, administrator and diplomat, and above all, as a successful military commander.

Personally I liked this one quite a lot. If you want to know how a 14th century army was organised and actually run this is the book I'd recommend.