The first Mississippi steamboat was a packet, the New Orleans, a side-wheeler built at Pittsburgh in 1811, designed for the New Orleans-Natchez trade. Packets dominated during the first forty years of steam providing the quickest passenger transportation throughout mid-continent America. The packets remained fairly numerous even into the first two decades of the twentieth century when old age or calamity overtook them. By the 1930s the flock was severely depleted, and today the packet is extinct.

Containing almost 6,000 entries, the directory includes a majority of combination passenger and freight steamers, but includes in a broader sense all types of passenger carriers propelled by steam that plied the waters of the Mississippi System. Each entry describes its steamboat by rig, class, engines, boilers, the shipyard where and when built, along with tidbits of historical interest on its use, demise, and/or conversion.

Also included are today's steam-powered river passenger carriers, the excursion boats Belle of Louisville, Natchez, and Julia Belle Swain, and the two tourist steamers, Mississippi Queen and Delta Queen.