Across:
   7. Job to describe such huge phenomenon? (8)
   8. Popular bracket of songs about end of war put in (6)
  10. Concept album's first half needs no introduction (4)
  11. Small samples of hits in teen production (10)
  12. Topical concern with jive music: jazz came from Africa ultimately (6)
  14. High flier, one named for Jefferson, seen at Yasgur's place (8)
  15. New one to follow: St Nick Carlos, who appeared at the Aquarian Exposition (7)
  17. Woody scion appeared in wood stock, and made it huger (7)
  20. Essence of age in crazy largest messy gathering (8)
  22. Joe was at Max's place and rocked out, swapping one Penny for another (6)
  25. In favour of Jefferson perhaps having more depth (10)
  26. Purloin the last cloak (4)
  28. Janis, or "Pearl" (little in name) initially played at iconic festival (6)
  29. Attending at time with less manners, he forced entry (8)
Down:
   1. Passed grateful ones who were at legendary concert (4)
   2. Maybe the sixties introduced the music... America provided the endings! (6)
   3. Prominence of group seen in rural New York in '69 (8)
   4. Ravi has rank in mess... he was at the big event (7)
   5. Johnny played his guitar at the muddy celebration of cold times (6)
   6. Able to grasp losing first two, but with third last out... deplorable! (10)
   9. Purloin the last missing cloak and dagger (7)
  10. Drug taken by policeman (3)
  13. Drop some ecstasy... exact herb to fix overdriven speaker (10)
  16. Confusion to fuel art with emotion (7)
  18. Clue about taking speed to turn into an ugly sore point (8)
  19. Personnel appearing around finish (just before 9)... brilliant act to close the famous show! (7)
  21. Sticking by good one during breather (6)
  23. Church is ruined with foundations of heaven and hell destroyed in entertaining show (6)
  24. Where the boys were drinking whisky in New York, or in Merry England (3)
  27. Bethel performer: Joan of Arc's origin surrounded by live mystery (4)