For the next book in the Grand Tour series its Mercury. This is the story about the engineer Mance Bracknell, that constructed the space elevator a generation ago almost that was a failure and when it colapsed killed more than 4 million people.
The story jumps back and fourth between the present time and the past when they created the space elevator. I was not totally sure I would enjoy the book as much as this type of back and fourth book is not the best type for me. But when the plot thickens and you get drawn into the story it was hard to put down as usual.