When the first personal computers were released in 1977, they each included a pre-installed version of the BASIC computer language along with example programs, including games, to show what users could do with these systems. While the manufacturers also had released commercial games that could be purchased for computers, the availability of BASIC led to people trying to make their own programs. Sales of the 1978 rerelease of the book "BASIC Computer Games" by David H. Ahl that included the source code for over one hundred games, eventually surpassed over one million copies. The availability of BASIC inspired a number of people to start writing their own games.