This invention provides a structured luggage system that allows for maximum versatility in luggage piece dimensions and using two luggage pieces. Each of the two luggage pieces can be converted from a full-height luggage piece to an approximately half-height piece with relative ease. The lower or main piece includes conventional wheels and a retractable/extendible handle for easy transport. The upper or secondary piece is adapted to stack on and be secured to the extended handle and (in full-height configuration) offer a secondary grip for added stability adjacent to the handle grip. The lower piece includes an inner central septum that can be sealed or opened to selectively define either a two-compartment piece or large, single compartment piece. Each compartment includes easily removable stiffeners in corresponding side pockets. By removing the upper compartment stiffeners, the pocket can be collapsed into a thickened top that includes the septum as the thickened top's inside face. By also removing the bottom set of stiffeners, the bottom compartment can be collapsed, allowing the entire main/lower piece to be compressed for easy storage.