In the Product Hunt Q&A, Dorsey said his most prized possession is a copy of "Tao Te Ching" a friend gave him.
This ancient Chinese text (pronounced "Dow Dé Jing") is attributed to Lao Tzu. It became the foundation for Taoism in the sixth century BC and was first translated into English in the late 19th century.
It is composed of 81 poems that reflect on the Tao, which is the force behind everything in the universe.
Among themes explored are self-mastery through humility.
All Square employees get a copy of "The Checklist Manifesto" on their first day of work, and Dorsey once tweeted that he's brought stacks of them to give away at Twitter.
In this 2009 book, surgeon and writer Atul Gawande argues that there are mistakes of ignorance and mistakes of ineptitude, and the latter category is most prevalent in the modern world. He believes clearly written guides and checklists are required for completing complex tasks to the best of your ability.
Gawande came to this conclusion when he and his team developed a safe surgery checklist that became a huge success around the world.
Dorsey is very into yoga, and you can find "The Yoga Sutras of Patañjali" in the Square library.
Yoga in the Western world is largely secular, but this Hindu book from the year 400 is a guide that not only teaches you how to perform yoga exercises but how to use those motions and breathing patterns to connect with God.