I think the guest was possibly referring to this paragraph from the Cascode Amplifier section.
While the C-B (common-base) amplifier is known for wider bandwidth than the C-E (common-emitter) configuration, the low input impedance (10s of Ω) of C-B is a limitation for many applications. The solution is to precede the C-B stage by a low gain C-E stage which has moderately high input impedance (kΩs). See Figure below. The stages are in a cascode configuration, stacked in series, as opposed to cascaded for a standard amplifier chain. See Capacitor coupled three stage common-emitter amplifier Capacitor coupled for a cascade example. The cascode amplifier configuration has both wide bandwidth and a moderately high input impedance.
They appear to be incorrect in their assertion. Looks fine to me.
I'm hoping that marie111000 will return and let us know which specific statement or section in the ebook she suspects is wrong. Then we can check to out.