In the past 54 years, the Grateful Dead's lineup has morphed more often than images in a psychedelic light show. Just like its hit-and-miss jams, not every version of the Dead is worth hearing.

With Dead & Company coming to town on July 2, here's a look at the three of the best - and worst - incarnations of rock's most famous improvisational band.

Dead Haight Street: The then not-so-famous members of The Grateful Dead pose at the corner of Haight and Ashbury in San Francisco around 1967. (Herb Greene / San Francisco Travel)

The best

1969-1970:

The classic Dead lineup featured all five founding members (and new percussionist Mickey Hart) digging back to their bluegrass roots in songs like "Friend of the Devil" and "Uncle John's Band." The band hit new heights, both in the studio (on Workingman's Dead and American Beauty) as well as onstage, including a fabled 1969 bootleg from SMU's McFarlin Auditorium. Much easier to find is Live/Dead, an official album recorded at San Francisco's Avalon Ballroom and Fillmore West.

1991:

Many Deadheads say the group was never the same after 1987's Top 10 hit "Touch of Gray" turned them into stadium superstars. Yet there were stellar shows aplenty on the 1991 tour, thanks in part to guest pianist Bruce Hornsby, who meshed perfectly with new singer-keyboardist Vince Welnick, formerly of the Tubes.

John Mayer (on screen), Bob Weir and others perform with Dead and Company, a Grateful Dead spinoff band, in December 2017 at American Airlines Center in Dallas. (2017 File Photo / Staff)

2004:

All of the post-Jerry Garcia reunion tours deserve an asterisk. But this 2004 lineup - dubbed simply "The Dead" - was one of the best, thanks to the addition of ex-Allman Brother Warren Haynes, arguably the bluesiest guitarist the group ever played with (aside from Jerry, of course). Second guitarist Jimmy Herring (Widespread Panic) added soul and funk to the mix. The current Dead & Company, with John Mayer on lead guitar, falls a bit short of this version. They last played in Dallas in 2017.

Jerry Garcia and The Grateful Dead perform at the University of Nevada, Las Vegas, in 1993. (1993 File Photo / The Associated Press)

The worst

1977-1978:

Clive Davis signed the band to Arista and immediately tried to get them to make hit singles - a big mistake, as evidenced by most of Shakedown Street (1978) and the horrendous disco version of "Dancin' in the Street" from Terrapin Station (1977). With singer Donna Godchaux and her pianist husband Keith Godchaux on board, this version of the Dead could be brilliant live. But the magic rarely translated into the studio.

1989:

The band performed some fine shows on its last tour with keyboardist-singer Brent Mydland, who died of a drug overdose in 1990. But 1989 will mostly be remembered as the year the Dead released its final - and arguably worst - studio album, Built to Last. It's also the year Dead tours officially turned into huge traveling circuses overrun by "trustafarians" and other clueless young stoners trying in vain to re-create the 1960s.

1995:

On his final tour, Jerry Garcia was a physical wreck as he struggled with heroin addiction, heavy smoking, obesity and diabetes, among other health problems. Predictably, his guitar playing ranged from adequate to just plain awful. On August 9, he died of heart failure at a drug rehab clinic at age 53.

Dead & Company with John Mayer perform at 7 p.m. Tuesday, July 2 at Dos Equis Pavilion, 3839 S. Fitzhugh Ave. $49.50 and up. livenation.com.

Thor Christensen is a Dallas writer and critic. Email him at thorchris2@yahoo.com.