On the Border (1974)

For their next album, On the Border, Henley and Frey wanted the band to break away from the country music style they were known for, moving more towards hard rock. Initially, the Eagles started off with Glyn Johns producing, but he tended to emphasize the lush side of their double-edged music. After completing only two songs, the band turned to Bill Szymczyk to produce the rest of the album. Szymczyk brought in Don Felder to add slide guitar to a song called "Good Day in Hell," and the band was so impressed that two days later they invited Felder to become the fifth Eagle. He appeared on only one other song on the album, the uptempo breakup song "Already Gone," where he performed the guitar duet with Glenn Frey. On the Border yielded a No. 1 Billboard single with "Best of My Love," which hit the top of the charts on March 1, 1975, becoming the Eagles' first of five chart toppers.