In the introduction to the book "Scott Joplin Complete Piano Works",
page xxviii, biographer Rudi Blesh writes: (begin quote)
Beginning with 'Leola' Joplin began adding the warning that would be
seen in most of his works to come: "Note: Do not play this piece fast.
It is never right to play 'Ragtime' fast. Composer." ...
Actually, any piece of music dictates -- within rather clear limits
-- its own proper tempo. Joplin's injunction needs to be read in the
light of his time, when a whole school of 'speed' players, whose sole
claim to fame was digital velocity, were ruining the fine rags. ...
Joplin's concept of 'slow' was probably relative to the destructive
prestos of the day. (end quote)