The Mapmakers by John Noble Wilford, Vintage, first published in 1981, revised and expanded in 2001.
I love maps. I don't think anybody can study geology and not come away with at least a healthy appreciation for maps. One of the very first things you learn in an intro geology course is how to read a map, and if you stick with it, a couple years later you'll learn how to create maps, an experience that involves a lot of traipsing about in an absurdly hot desert with a Brunton compass, a homemade duct-tape-and-plexiglass clipboard, a pocket full of colored pencils, and an expression of extreme befuddlement that transforms into alarm when you realize that in your eagerness to measure the strike and dip of that lovely sandstone outcrop you've come just six inches away from stepping on a rattlesnake.
I didn't keep drawing maps in my grad school research, but I did spend a lot of time with the data collected by nineteenth century British surveyors as part of the Great Trigonometrical Survey of India. Most of my field work involved hunting through even hotter deserts (full of even more poisonous snakes) for the old survey monuments atop hills and towers and temples, always the highest point for miles around. I didn't know when I started grad school that I was signing up to haul GPS equipment up hundreds of steps to a temple outside Rajkot beneath a full moon in the middle of the night, because that's the most sensible time to work outside in western India in the summer, searching for a pinpoint survey marker on a twelve-inch-square stone that might have been carried away to build somebody's house a hundred and fifty years ago. (Advice to students considering a graduate education in geophysics: Ask first if the field work involves carrying car batteries up mountains.) I very much doubt the men who surveyed India would have suspected their careful angles would be useful long after their deaths, not for the purpose of measuring the land, but because the continent itself was changing shape beneath them.
I love maps. I love how they're made, I love how beautiful they are, I love what they show us, I love knowing how to make them myself, and I do not trust anybody who refuses to learn how to read one. The first thing I do when I stop by a visitor center at a National Park is find the geologic map of the region to discover what's beneath my feet. I think it's safe to say I am exactly the target audience for this book.
The Mapmakers is a very thorough history of mapmaking, starting with the oldest known maps and carrying all the way through to cosmological maps of the universe, including detail about the instruments and techniques, projections and navigation systems, and, most of all, the lives of the surprisingly small number of explorers, surveyors, families, and scientists who were, up until the twentieth century, responsible for a very large number of the world's maps.
The revision and expansion twenty years after the initial publication date was necessary. The science and art of mapmaking has undergone a massive revolution in the last few decades, with the rapid development of orbital imaging and navigation technology. It's such a thorough change in how maps are made and produced it's almost an entirely different science now, one that's dependent on computing and satellite technology rather than on-the-ground exploration. The results are more complicated and contain far more information than the even the most detailed two-dimensional map can handle, but the philosophy behind them remains the same: we will always want to know where we are and what's around us.
I found the entire book interesting, but one chapter that really struck me was about the symbolic, mythological maps popular in the early Middle Ages. These were maps created for the purpose of telling a story--a story that reinforced Christian dogma, usually--and were never meant to be an accurate representation of the world. It wasn't that the mapmakers lacked the knowledge to create a true-to-life representation of the world (although they often did; they didn't travel much), but that it was never the conceptual goal of such maps to show rivers and mountains or borders, or to tell anybody how to get from here to there. They were maps intended to tell stories about morality and sin, about monsters and myths. It is so fascinating to me that the very medium we use today to analyze the deep history of a mountain range or to find the directions to the nearest restaurant with a lunch buffet is the same medium popes and bishops used in the twelfth century to stir up fear among the faithful regarding the impending arrival of the armies of Satan.
Maps are such a fundamental part of how we see the world, it's hard to imagine not having that perspective. When astronaut John Glenn was orbiting the Earth in 1962, he remarked that it looked just like a map. He was seeing the Earth as it is, from a vantage few would ever have a chance to experience, and it looked like a map. That's how ingrained the imagery of maps is in our consciousness, and the history of how this one tool has evolved and changed over millennia is an intriguing cross-section of human history even if you aren't a map-lover. (But why wouldn't you be? What's wrong with you?)
(Note of somewhat unrelated interest: John Noble Wilford is the same author who wrote, among many other things, The New York Times's report of the first Moon landing in 1969, a lovely article that is well worth reading.)