What is the evolution of the Stenographer's Notebook?
Type of answer I'm looking for: when first used, where, why the
specific standard size of today's pad, why the line in the middle, why
flip up vs sideways, why green tint not yellow, Evolving forms of
usage

Hi, Ome10!

I'm not sure about the early origins of the steno pad, although the
typewriter was first invented in 1874 and the first stenography
machine in 1879, so it could be that the steno pad first appeared
sometime between the two.  Stenography itself is credited as
developing as early as the 1600s, shortly after the quill pen was
invented.

Variations of the modern steno pad evolved during the 1930's, as the
need for an office assistant, secretary or stenographer became more
common.

Having studied stenography myself, however, I can tell you that the
reason for the line in the middle was a time saving device, as the
stenographer only crossed one-half of the page at a time, thus saving
the time it would take to move back and forth; the size of the pad was
specifically designed to sit comfortably on one's lap, as secretaries
were expected to work without a writing surface; the cardboard backing
was also designed to be sturdier than pads otherwise available for the
same purpose; and the color (probably added at a later time, during
the 1940's or 1950's) when paper manufacturers became aware of the eye
strain involved with looking at pure-white paper.

Tracker Mo
http://www.trackermo.com

HI,
Glad someone with experience clarified the vertical line.  I expect
the pages flip upward for the same reason: to save time, since
flipping them to the left (as when reading a book) would require the
stenographer to regrasp the block; flipping them to the right would
involve the writing hand, and both would be less convenient when
flipping back to tell the boss what he had previously said.