The book, "Season One" is a follow-up to Kobe's NYT Bestselling work, "The Wizenard Series: Training Camp" ... which focuses on a young hooper named Reggie, who dreams of being a basketball superstar.

Vanessa celebrated the news on Instagram Tuesday ... saying, "Welcome back to Dren! We hope you are all ready to catch up with the West Bottom Badgers for another magical basketball season."

The book shares a quote from the late Kobe Bryant after the title page ... which says, "To young athletes who commit to doing the hard work. The process always pays off."

The book's author, Wesley King, reflected on the book drop -- saying, "Official release day. Bittersweet without my collaborator, but grateful to see the words live on. This is a book about chasing your dreams."

Of course, Kobe's second act after basketball was just taking off ... from business partnerships to winning an Oscar for the short film, "Dear Basketball."

#RIP