Get your hands on any book by Michael Sull who in my estimation is primarily responsible for keeping the art of Spencerian handwriting alive, preserving the history and many of the old exemplars, many of which are kept in the archives and salt caves where IAMPETH stores the originals. Most have been scanned for online viewing, so you will enjoy exploring that site. He used to run a week long course in Ohio where Spencerian writing had it's roots. He would take you to pick up oval shaped stones at Lake Erie, similar to those Spencer used to inspire his graceful script. ( I still have the stones I picked up to remind me to be mindful of my oval shapes) He took his students to visit Spencer's gravesite and would share everything he could with his students in that short week. He also raised funds to have a Spencerian Monument built in Geneva, Ohio, Spencer's hometown. It was truly a week to delve in to the history of Spencerian writing and learn the nuances. Now the same seminar is still running, but Harvest Crittenden has taken over and she is carrying on where he left off. Anyone is welcome to attend. They used to have a beginners week and then a more advanced week and it was certainly worth every penny. Michael also loves hand written correspondence and if you send him a letter, he will definitely write back with answers to any historical questions you might have. He's on the road a lot teaching and I know he often attends pen shows where he sells his most recent book on handwriting.
Also from Spencer's own words.....
Origin of Spencerian Penmanship
Evolved 'mid nature's unpruned scenes,
On Erie's wild and woody shore,
The rolling wave, the dancing stream,
The wild-rose haunts in days of yore.
The opal, quartz and ammonite,
Gleaming beneath the wavelet's flow,
Each gave its lesson - how to write -
In the loved years of long ago.
I seized the forms I loved so well -
Compounded them as meaning signs,
And to the music of the swell
Blent them with undulating vines.
Thanks, Nature, for the impress pure,
Those tracings in the sand are gone;
But while love shall for thee endure,
Their grace and ease will still live on.
-Platt Rogers Spencer