Bivalvia, commonly called the bivalves, is a taxonomic class of marine and freshwater molluscs that have a laterally compressed body enclosed by a shell in two hinged parts. This class includes the clams, oysters, mussels, scallops and numerous other families. The majority are filter feeders and have no head or radula. The gills have been modified into ctenidia, specialised organs for feeding and breathing. The majority of bivalves are infaunal and bury themselves in sediment on the seabed. Others are epifaunal and attach themselves to hard surfaces. A few bore into wood, clay or rock and live inside these substances. Some bivalves, such as the scallops, can swim.

The shell of a bivalve is composed of calcium carbonate and consists of two rounded halves called valves, which in most species are more or less mirror images of each other. The valves are joined together at one edge by a flexible ligament which, in conjunction with nearby interlocking "teeth" on the two valves, are known collectively as the hinge. This arrangement allows the shell to be opened and closed without the two halves becoming disarticulated. The shell is typically bilaterally symmetrical, with the hinge lying in the sagittal plane. The adult maximum shell size of extant species ranges from 0.52 millimetres (0.020 in) in Condylonucula maya (a nut clam) to a length of 1,532 millimetres (60.3 in) in Kuphus polythalamia, a kind of shipworm. However, the species generally regarded as the largest living bivalve is the giant clam Tridacna gigas, which can weigh more than 200 kilograms (441 lbs). The largest extinct bivalve known is a species of Platyceramus, whose fossils measure 2 to 3 metres (6 ft 7 in to 9 ft 10 in) in length.

Paul Brandon Gilbert (born November 6, 1966 in Illinois, USA) is an American guitarist. He is well known for his technical guitar work with Racer X and Mr. Big, as well as many solo albums and numerous collaborations and guest appearances with other musicians.

He has been voted number 4 on a list in GuitarOne magazine of the "Top 10 Greatest Guitar Shredders of All Time", as well as a spot in Guitar World's 50 Fastest Guitarists of All Time list.

Gilbert was raised in Greensburg, Pennsylvania. Around 1981-82, he first contacted Mike Varney, founder of Shrapnel Records, asking for a gig with Ozzy Osbourne. At the time, Varney couldn't think why Osbourne would want a 15 year old guitarist, but after listening to his demo he changed his mind. Gilbert was featured in Guitar Player magazine at the age of fifteen. They talked for the next 3 years, until Paul went to L.A. for the GIT (Guitar Institute of Technology), and then was ready to record Racer X's debut album Street Lethal.