H. P. N. Gammel, early Texas bookseller, collector of Texana, and compiler and publisher of Gammel's Laws of Texas, was born to Neils (Niels) Hansen and Mittie Marie (Brugger) Gammel at Grenå, Denmark, on September 24, 1854. As a young man he immigrated to America, first to Chicago in 1874, then to "gold fields in the West," before arriving in Galveston, Texas, in 1877 and walking the rest of the way to Austin. There for a time he and his brother Neils sold trinkets; when Neils left town, Hans built a shelf between two chinaberry trees, at Eighth Street and Congress Avenue, where he bought books for five cents and sold them for ten cents, reading and learning from them in the meantime.
Though he had little knowledge of English when he sailed to America, Gammel's ten-cent business became the basis for one of the first bookstores west of the Mississippi to carry a large assortment of miscellaneous literature, law books, and Texana. At its peak, its collection was one of the largest of this type in the state. When Gammel became a publisher, his first title was John C. Duval's Early Times in Texas (1892). Other notable titles were C. W. Raines's Bibliography of Texas (1896), Noah Smithwick's Evolution of a State (1900), and a reprint in 1906 of Journal of the Continental Convention of the State of Texas (1875).
Gammel's most important accomplishment and the chief basis for his widespread recognition was the result of an early experience. He was still a newcomer to Texas when, in 1881, the old Capitol in Austin burned. From the debris scattered on the Capitol grounds, young Gammel gathered wet papers and charred documents, loaded them in a wagon, and took them to his home. He and his wife gradually dried the pages on clotheslines and stored them with their belongings. Years later he sorted and edited the crinkled papers, then published them beginning in 1898 as the famous first ten volumes of Gammel's Laws of Texas, 1822–1897. This work won immediate acclaim, and with the addition of other volumes in later years the set came to be a basic item in law libraries across the state.
Gammel was a Mason, a Knight of Pythias, and a Woodman of the World; he was a Lutheran when he arrived in America, but he and his second wife attended the Presbyterian church. As a young man in Denmark Gammel was married to Anna Marie Andersen, and one daughter was born to them there. After Anna's death from typhoid in late 1888, Hans married Swedish-born Josephine Matilda Ledel, who bore him eight children. His youngest, Dorothea, remained with him at their home until his death, and in his late years she assisted him in cataloging the extensive private library of Texana for which he had been widely recognized. Gammel died on February 11, 1931, in Austin.