I didn’t really used them. Monarch Notes were more popular in Connecticut in the ‘70s.
I did a lot of skimming in order to get the same effect, or asked classmates who actually read the material.
After 25 pages of Moby Dick, I knew that book wasn’t for me.
Plus my little community had the advantage of a library that had been initiated and continually kept up-to-date by Andrew Carnegie's Trust Funds. Also, one wing of the library was sort of a museum of the past history of the town, once the county seat. Spinning wheels, historic furnishibgs and tapestries, flintlock and percussion rifles and muskets, and swords from the Revolutionary and Mexican and Civil and Spanish Wars.
Head of my 6th grade class, with my 99.6% grade average, 0.2% more than Doris Cairns, whose dedicated striving only got her disappointing 99.4%. No "Cliff's notes for us in those days, everything earned.
That was June, 1948, a great and glorious time for our nation, before the coldness of the Cold War and Korean and Vietnam Wars turned our attention away from the very professional highly honored school teachers who demanded the exercise of one's intellect, an age wrapped up and put away when unionization of the NEA turned public schooling an intellectual slime pit.
Except for my own children, with me snapping at their heels to keep them moving through and past Ed-degreed but inept teachers (except for athletics, can't fool that realm where performance is everything).