Short answers, pulled from the story.
The New Jedi Order consists of 19 novels published between 1999 and 2003. Additional related stories, including e-book novellas and comic books published as late as 2010-2011, bring the total number of New Jedi Order-related stories to 26.
In 1998, Sue Rostoni (managing editor for Lucas Licensing), Shelly Shapiro (editorial director for Del Rey Books), and novelist James Luceno plotted the series together. Luceno described creating a series bible with story arcs and a character database that was distributed to the authors hired to write individual books.
Chewbacca dies in Vector Prime, the first book, when the planet Sernpidal's moon is pulled into it by the Yuuzhan Vong. The decision was made by the book editors, who submitted a list of characters they wanted to kill to George Lucas; Chewbacca was selected because he was not on the list of characters Lucas protected. George Lucas approved the death.
Following Disney's acquisition of Lucasfilm in 2014, The New Jedi Order and most other existing Star Wars spin-off works were declared non-canon and rebranded as Legends. The death of Chewbacca in Vector Prime was cited as a key factor in the decision to revoke the Expanded Universe's canonical status.
The Yuuzhan Vong are an alien species that emerge from outside the Star Wars galaxy and launch an invasion 21-25 years after the events of Return of the Jedi. They are distinct from every other Star Wars enemy because they exist outside the Force entirely, making them invisible to Jedi sense. Their character Nom Anor originated in the Dark Horse Comics series Crimson Empire.
In January 2025, Variety reported that a film titled Star Wars: New Jedi Order, starring Daisy Ridley and directed by Sharmeen Obaid-Chinoy, was in development.