I've read this several times before, but apparently not since 1998. Scary book, scary movie.
On page 272 a "Jo block" is mentioned. I looked 'em up, they are standard gauge blocks of varying size that are combined for measurement in a machine tool. More or less!
On page 313 a quote "Would that my subjects had but one neck...", which pretty much is what is in the standard quote sites, and is attributed to Caligula.
A boy and his pet, or vice versa, head out to the woods for a little alone-time from the stresses of societal demands... I think I only read this one five times since junior high. I love the teen girl divorcing her parents in a 1954 book!
Twins with telepathic talents maintain communications between a spaceship surveying planets to settle and Earth. Read again. And again. This time I learned that "sasparilla" is a variation of the original "sarsaparilla". Or vice versa. Or neither!