On every double spread there is a letterform & information about its designer. Johann Steingruber's Architectural Alphabet (1773) is my favourite that's featured in the book, none of the buildings were actually built but the letters provide a very detailed and accurate architectural plan.
I'd quite like to live here:
Another letterform I noticed in the book was this one, The 'Interrobang,' a mixture of a question mark and an exclamation mark which I didn't know actually existed. It was designed by Martin Speckter in 1962 to create neater lines in advertising copy.