On page 42, it reads:
"The less-used diminished seventh chord takes a diminished triad and adds a minor seventh on top."
A diminished seventh chord in the key of C, with B as root, according to the book's text, would (incorrectly) be:
B D F Abut this is actually the B half-diminished 7th chord.
A Bdim7 actually has the notes:
B D F Ab
"The less-used diminished seventh chord is composed of a diminished triad and a diminished seventh interval."
to be continued...