You may ask, ''Where have you been since the '60s?'' But, although I'm the same age, I didn't know who Jerry Garcia was until three years ago. While on a family vacation in Kona, Hawaii, I checked into Jack's Diving Locker about 8:30 AM for the 9:00 AM dive. After checking out my gear, I was introduced to Jerry, a rotund 50-year-old with a huge salt and pepper beard. We didn't say much on the ride in the front seat of the dilapidated pick-up truck to the boat. The fun started on the boat ride our to our dive site. In an attempt to start up a conversation, I mentioned that this was my first time in Kona. Jerry said he would come six to eight times a year. ''What type of business are you in, Jerry?'' I asked him. ''Music.'' ''Are you a distributor or what?'' ''No, I'm a musician.'' ''Do you play in a band?'' ''Actually, I play in 3 bands.'' ''What type of music?'' ''One of the bands plays rock and another bluegrass.'' ''What's the name of the band?'' ''One of the bands is The Garcia Band.'' I still didn't have a clue. We went on a very shallow dive of about 35 feet in which we explored volcanic arches. Jerry found a small octopus, we saw some turtles, Moray eels, coral and other sea life. I returned to the surface with my assigned buddy while Jerry and his dive buddy stayed down. Jerry was the last one back to the boat after a bottom time of 109 minutes on one tank of air. While he was drying off, I noticed his towel was from the Ritz-Carlton Mauna Lanai, which I recognized as one of the most luxurious and expensive hotels on the island. ''Hey, Jerry, are you staying at the Ritz or did you rip off the towel?'' I ask, ''No, I'm staying there,'' he told me with a big smile. ''What were you doing down there so long?'' ''I like to sing underwater.'' ''How can you sing underwater with the regulator in your mouth? How can you move your lips?'' ''I don't know, but I can hear myself. I like to float around neutrally buoyant, sometimes upside-down and make up songs.'' That evening I discussed the dive and my encounter with Jerry with my wife and 18-year-old daughter, Julie. My wife suggested that maybe I had met someone famous, and I said, ''No way! He was a wonderful guy but he looked like a bum.'' Since we had to go back to the dive shop the next day to pick up my dive video, we decided to ask who Jerry was. A dive shop employee told us, ''That was Jerry Garcia.'' It wasn't until I asked Julie if she'd ever heard of Jerry Garcia that I finally ''got a clue!'' ''Dad, he's the leader of The Grateful Dead!'' she answered in disbelief. Knowing that he dives just about every day that he's on the island, we met the dive boat at the dock later that afternoon. Spotting Jerry on the boat backing in, I asked if he had stayed down another 109 minutes? ''No, we were a little deeper today,'' he replied. ''My daughter figured out who you are,'' I told him and he smiled as he sat down on the dock to talk to us. ''I know you're on vacation and I don't want to start a commotion with all the other people from the dive boat around, but could you please sign an autograph for my daughter?'' I asked him. ''Sure,'' he said, ''but don't worry about these other people -- that's the rest of the band!'' My life is richer for the brief encounter with this unique man. I'm sure he enjoyed the few hours of repartee with someone who had no idea of his immense talent and fame.