Today marks the 10-year anniversary of Tegan and Sara's fourth album, So Jealous.

The disc was their third effort on Vapor, and their first to really make a dent on the sales charts, with more than 200,000 copies sold and a gold certification.

The twin sisters announced on Monday that they will be releasing a book on the making of So Jealous and their ensuing years of touring and promotion. Titled Jealous X, the book will also include three discs of musical content that includes previously unreleased demos and b-sides, new remixes and covers (retrieved via POZ):

"It was without a doubt a huge turning point in our career, and a big part of how we got where we are today," they wrote. "We can't let something like this pass by uncelebrated!"

Pre-orders for Jealous X will begin in December on the duo's website, and they'll be releasing more information in the coming weeks.

Tegan and Sara are currently on tour with Katy Perry. Check out those dates here:

09/16: Anaheim, CA @ Honda Center

09/17: Anaheim, CA @ Honda Center

09/19: Los Angeles, CA @ Staples Center

09/20: Los Angeles, CA @ Staples Center

09/22: San Jose, CA @ SAP Center

09/23: San Jose, CA @ SAP Center

09/25: Glendale, AZ @ Jobing.com Arena

09/26: Las Vegas, NV @ MGM Grand Garden Arena

09/29: Salt Lake City, UT @ EnergySolutions Arena

09/30: Denver, CO @ Pepsi Center

10/01: Lawrence, KS @ Liberty Hall

10/02: Dallas, TX @ American Airlines Center

10/03: Dallas, TX @ American Airlines Center

10/04: Austin, TX @ Late Night Show

10/05: Memphis, TN @ FedEx Forum

10/06: Tulsa, OK @ BOK Center

10/08: New Orleans, LA @ New Orleans Arena

11/11: Seattle, WA @ The Paramount Theatre

11/12: Portland, OR @ Roseland Theatre

11/21: Honolulu, HI @ The Republik

(Dates in bold are with KP.)