Perhaps because it is the first book published in what would become the United States. The so-called Bay Psalm Book was a project of extraordinary ambition, undertaken by the Puritans of Massachusetts not long after they crossed the Atlantic and began to live around Boston. At Cambridge, a printing press, brought over from England, began to issue The Word: first a freeman’s oath, then an almanac, and then the great project of a book of psalms. This would be useful in church—the Puritans, surprisingly, loved to sing—and it would show a doubting Europe that they were people of culture, ready to take on the world. The book is crude in ways—lines do not always align perfectly—but when you consider what they were up against, thousands of miles from London, it’s a remarkable achievement. There are decorative elements here and there, and bits of Hebrew type dropped into the text (were they showing off?). But if it speaks a bit proudly, it also warns against the sin of pride. The reason that this copy is so valuable is that it is the simplest. Only 11 copies are known to exist, and this one is considered the most perfect, still in its original binding. (via The Bay Psalm Book: the first volume published by the Puritans in the United States) http://www.wdl.org/en/item/2834/zoom/