The glossary notes Claudia Bush was a grad student at Idaho State University who corresponded with Dick while working on her master’s thesis.
In a letter to her Dick tells her about a dream he had that was trying to direct him to a book of some significance. All he could see in the dream was a hardbound blue book with a title that ended in the word ‘Grove.’ He eventually finds a book in his library that matches this description, a biography of Warren G. Harding called The Shadow of Blooming Grove, but it turns out to be ‘the dullest book in the world.’ In a postscript he tells Claudia to never take dreams too seriously.