Showgoers at recent Heart concerts have been privy to the first details about ‘Strange Euphoria,’ the forthcoming box set from the group which is set for release on June 5, just in time for the band’s summer touring season.

A flyer handed out after the Heart show in New Kirk, Okla. reveals that the box set will contain 50 tracks featuring a mixture of previously unreleased demos and rarities (including hopefully, the long-desired original versions of the ‘Magazine’ album tracks), live tracks and of course, their “chart-topping hits.”

The four disc set will also include a DVD of the rare 1976 television performance, plus new track-by-track commentary from Ann and Nancy Wilson.

Ann and Nancy announced the release date themselves during an on-stage interview at South by Southwest, and also revealed that their new studio album ‘Fanatic’ will be out on October 2, which will be in the same time period that their memoir will be released.

Longtime Heart associate and collaborator Sue Ennis is clearly, enthused about the box set and shared with fans, “Believe me, it IS too cool! So many unearthed rarities. A goldmine for Heartmongers who really know this band.”

Ennis previously tweeted about the set and said that she was “excited that fans will soon hear some favorite songs that never found a home on the major label records.”

Heart’s summer tour schedule kicks off officially on June 29 in St. Paul, Minn. and will roll through September with additional dates likely in conjunction with the new album.