It has been 40 years since the Marshall Tucker Band began changing the world of music by blending rock, country, jazz and blues into one. Their musical creativity and feel-good tunes have been winning over fans in the southern rock world ever since.

"The fun part about what we did was that nobody ever really started to do it like this," Marshall Tucker Band's lead singer Doug Gray tells Ultimate Classic Rock. "We never knew what we were doing [laughs]! We knew bands like the Allman Brothers had been out there for years. You have to realize that even back in the real old days, Gladys Knight and bands like Four Tops were out doing shows, but their shows were really shows instead of just standing there and playing music"

He continues, "then the Allman Brothers and other people from the classic rock movement started playing jams in between [around] 1965. If you take something like Eddie Floyd's 'Knock on Wood,' we would put a whole section in there that did something different; more than normal. We wouldn't always know exactly what we were doing either, which made it even more fun."

"Back when we first started, no one knew just what kind of music we were," Gray explains. "We were a little bit jazz and a little bit country. I mean, basically because of the way I talk, you have country, but I don't talk like I sing!"

While Gray and the original members of the Marshall Tucker Band have enjoyed many high moments throughout their career, their musical journey also consisted of many devastating times, including deaths within the core of the band -- lead guitarist Toy Caldwell, his brother, bassist Tommy Caldwell and rhythm guitarist George McCorkie have all passed on -- throughout the years.

To commemorate the 40 years of music, the Marshall Tucker Band has released their 'Greatest Hits' album, which contains 14 original recordings of the songs that made them a household name, including 'Fire on the Mountain,' 'Heard It in a Love Song,' 'Can't You See' and more.

"We got a lot of airplay back in the day, and we still get a lot of airplay," Gray says proudly. "I think the reason behind most of our airplay today is because we created so many memories with the early parts of our time. People like your mom and dad would come see us live back then. They'd have kids, and their kids would have kids."

"Now, if we go play a fair show and sign autographs afterward, we get little girls coming up saying, 'My Grandpa wants an autograph, and he wants me to take a picture of you because he has a photo on the mantle of one he took with you 35 years ago!' I usually make them go over and get them, and then we all take another group picture. You are talking about 40 years ... that's a long time. I don't even realize how long that is all the time."

In addition to the 'Greatest Hits' project, Gray has also released a never-before R&B solo album, 'Soul of the South.' The tunes found on 'Soul of the South' were recorded by Gray 30 years ago.

"It was done a year after Tommy had died in a car wreck," Gray notes. "Putting it together, I just wanted to do something that had some real soul with old James Brown type of licks in it ... songs that would make people think."

'Soul of the South' contains eight songs, including the cover song, 'More Today Than Yesterday.' "I wouldn't even attempt to do [that song] today for the simple reason that I couldn't sing the damn thing," Gray laughs. "But 30 years ago, I just didn't have anything to do, and we had a studio so I said let's go put it together. When we put it together, people wanted it, and that put me in a dilemma because we still had the Marshall Tucker Band."

The decision he made shows Gray's loyalty to his band and the legacy they had created together: "So instead of leaving and doing the Doug Gray thing, I decided that since we already had nine years in the Marshall Tucker Band - which is longer than most of my marriages lasted [laughs] - it would be smarter to continue to go out there with Marshall Tucker Band."

It wasn't until a little over a year ago when Gray's record label personnel asked the legendary singer to pull the collection of tunes back out to give it a listen. "We cleaned it up a little bit, and they loved it," Gray says. "They wanted to put it out with the 'Greatest Hits' album, and I said that it sounds like a good idea, but we'd better explain to people why it's a 'soul' record instead of something like that."

While the 'Soul of the South' album is new to fans, don't expect Gray to launch into a solo tour in support of the project. He does, however, predict the Marshall Tucker Band will incorporate at least one special song from the album into their live shows.

"We've got one song that we're going to play, and that will be 'Sandman,'" he says. "That song does have the original band [on the record], minus Tommy, and that is the reason I want to do that particular song."

Through the laughter and tears, Gray sometimes finds it hard to believe that the Marshall Tucker Band has been making such an impact on music for 40 years, but says he is truly able to enjoy the ride better now in his early 60's.

"It's more fun now because I'm not all jacked up and smoked out," Gray admits. "It's important that people know I did that and had a good time doing it, but there is a point in time when you have to stop. I chose that time in 1989."

"Everything about the last 40 years has been a wonderful ride," he reflects. "I don't think I would ever want to change anything. I think trying to change the band continuing on would be the craziest thing in the world. Some times it feels like we're just getting started!"

Watch the Marshall Tucker Band's Performance of 'Can't You See'