Having some idea of your interests from your posts over the years, I suspect you have already read this book: 747: Creating the World’s First Jumbo Jet and Other Adventures from a Life in Aviation which I (as an aviation enthusiast) found fascinating.
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That’s an expensive book, but my library has it and I just placed a hold.
I read a while back that Boeing almost sold the rights to the 737 to pay for some of the 747 development costs. I bet they are glad they didn’t.
Boy, you are right there. Look at the 737 today!
You’re going to love that book!