This Saturday the fourth annual Boston Book Festival (BBF) will attract thousands to Copley Square for twelve hours of free book-related events. The festival’s events include presentations and panels featuring internationally known best-seller writers, scholars, critics and commentators, but also literary agents, bloggers, advice columnists and a wide range of journalists. There will be programming for children, teens and families; writing workshops and competitions; and spoken word and music performances. All daytime events are free, but most require First Night-style lining up to get into spaces with limited seating.

Though there is one discussion of new interpretations of Homer’s “Iliad” and another of J.R.R. Tolkein’s “The Hobbit,” most offerings look to the future rather than the past. Among them are “Graphic Novels,” “Flash Fiction,” “What’s Next for Women?” and “Self-Publishing with Blurb.”

Robert Ford, winner of both the Pulitzer and PEN/Faulkner awards, will give the Saturday night keynote. While tickets for Ford’s presentation cost $10, there is no charge for the Kids’ keynote speaker, Lemony Snicket, or rather his “representative” Daniel Handler ( 1 p.m., Old South Sanctuary). Paparazzi will also be looking for other kid lit notables like Curious George and Llama Llama. Other big names include Dominican-American Junot Diaz, frequent short story contributor to The New Yorker and winner of the 2008 Pulitzer Prize for Fiction for “The Brief Wondrous Life of Oscar Wao.”

Mystery novel fans have plenty to choose from including talks by Alexander McCall Smith (No. 1 Ladies’ Detective Agency and Isabel Dalhousie series) and Boston’s own Hank Phillippi Ryan, spilling the secrets of “How to Write a Crime Novel.”

Friday night at 7:30 p.m. at Old South Church, BBF kicks off with its only other ticketed event: a panel discussion among five authors whose book-length works have been turned into films and television shows. Among them are Buzz Bissinger (“Friday Night Lights”), Rachel Cohn (“Nick & Norah’s Infinite Playlist”), and Andre Dubus III (“The House of Sand and Fog”).

This panel marks the culmination of “Book to Film,” a new series co-sponsored by the BBF and ArtsEmerson, exploring movies based on popular and award-winning books for adults and children. For the past two weekends relevant films were shown at the ArtsEmerson’s Paramount Center. Two of the 11 flicks-based-on-books were by Dot’s Dennis Lehane: “Mystic River” and “Gone, Baby, Gone.” 

In just four years, the BBF has become one of the red-letter days on the Boston cultural calendar. Organizers estimate that about 30,000 people took part in last year’s BBF, representing a 20 percent jump from 2010. A street fair in the square features exhibitors offering rare tomes and bargains and artist performing live music throughout the day.

BBF’s One City One Story (1C1S) initiative disseminates free copies of a short story throughout greater Boston, culminating in a town hall discussion with the author ( 12:45 p.m., Boston Common Hancock Hotel). This year’s selection, set in the North End, is Anna Solomon’s “The Lobster Mafia Story,” centering on Marcella’s feelings about her husband’s criminal past.

Dot residents still have time to be part of 1C1S. Copies of “The Lobster Mafia Story” are at all branch libraries and BCYF community center locations in Dorchester and Mattapan.

To download Solomon’s story in a variety of languages and formats or simply to browse through all the BBF options, go to bostonbookfest.org.