Okay, confession time: this is the fist McCullough I've read. His books have been recommended to me dozens of times (especially John Adams), but I have always had this aversion to "popular" historians. There are certain popular historians that I just distrust--they have published too much to have done much of the work themselves--or to really dive into the material.
McCullough does not appear to be one of those "popular" historians.
This book is a collection of essays, first published in 1991. The majority of the essays are brief, biographical sketches of some fascinating people--some of whom I had never heard of, many of whom don't follow into my usual categories of historical interest. But each essay was wonderful. He introduced me to some people I would love to know more about, such as Miriam Rothschild. He told the jaw-dropping story of the building of the Brooklyn Bridge and the railroad line across Panama (before the canal).
I loved his writing style--he doesn't get bogged down in details like so many historians, but somehow senses exactly what we the reader need to know in order to understand.
Highly recommended. I may even tackle John Adams one of these days.