What is the origin of the lava lamp?

The Lava Lamp was invented by Edward Craven Walker and first went on sale in 1963. Walker was inspired by a lamp he saw in a bar 15 years earlier, and eventually perfected the "lava" recipe, using a combination of oil, wax, and various other solids. Originally marketed in Europe under the name Astro Lamp, it was eventually brought to the states by two American entrepreneurs and sold as the Lava Lite lamp.