Get to know each other; share information and/or inspiration; encourage discussions on any of a variety of topics; build team knowledge and/or enthusiasm about a relevant topic . . .
Enough copies of a book for everyone to have one. The organization can purchase them (with possible bulk rates) or perhaps borrow them from libraries. If there can't be enough for everyone, give more time and ask people to read and then pass copies to others.
By vote, consensus, or by the organizer deciding on a book, announce the current book selection. Schedule plenty of time for everyone to read the selection. Schedule a date, time, place for a group discussion.
Each person checks out and reads the same book. The discussion can be free-form or led by one person. A focus can be how the team is inspired or informed and what impact it may have on future team activities.
The process could be discussed - e.g., perhaps people want to rotate the choosing of a book, or have the discussion online.
Online instead of in-person discussion. Afterwards, donate all but one copy of the books to a charitable organization, or circulate to another team/organization. See also the Teampedia activities What have you been reading?, Library, and Little Free Library