This week, doctors saved a baby using a device made on a three-dimensional printer, NASA announced it is investing in 3D food-printing technology and a U.S. company was forced to remove plans for a working 3D printable handgun from its website.

In short, the technology that was virtually unheard of a couple of years ago -- except among ultra-nerdy tech circles and in sci-fi book clubs -- is now making headlines around the world on an almost daily basis.

So what is it exactly?

Three-dimensional printing -- and many insiders prefer the term "making" in order to differentiate from the traditional idea of printing -- is at its most basic level the process of creating a digital 3D design, then slicing that design into layers and printing those layers one at a time until the final product takes shape.

Everything from the soles of running shoes to a new coffee cup can be made using this technique.

How does it work?

Three-dimensional printers typically use rolls of acrylic, ABS or metal as the raw material which is then fed into the machine.

Guided by computer-assisted design software (CAD), the printers melt down that raw material and repurpose it into solid objects by depositing droplets one layer at a time.

That material is then melded into shape using a precision laser, following the specifications set out in the CAD drawing.

As these layers -- which can be microscopically thin -- add up, the 3D object slowly takes shape.

When they were first invented 30 years ago, the original models of these machines were large, expensive and could only be operated by experts. But several companies are now producing hobbyist-sized versions that can be purchased for around $1,000 dollars and used at home by "makers."

What are the advantages of 3D printing over traditional manufacturing?

Traditional manufacturing typically requires large blocks of material such as steel, which is then cut away using a CNC machine or a lathe to create the final product. As a result there is a much larger amount of waste than with 3D printing, which leaves behind almost no waste material whatsoever.

Other traditional forms of manufacturing, such as tool and die, require forms to be built which then hold the liquid raw material as it is poured in and allowed to cool -- a process that typically requires large machinery, workshops and assembly-line support.

Three-dimensional printing, by contrast, can be done in anyone's garage or basement, often with a microwave-sized device.

And unlike massive robotic assembly-line machinery, which needs to be retooled every time a new product is introduced, 3D printers can adjust to a new product-line just as fast as new software is introduced.

As a result, some experts have compared the advent of the 3D printer to the invention of the home computer or the online search engine -- forecasting that it will change the world of manufacturing.

How can I get one?

Hobbyist-sized versions can be purchased directly from manufacturers such as Cubify and MakerBot, and Staples announced it will begin selling 3D printers on its website and eventually in stores.

Stratasys offers a range of printers from desktop models to commercial sized units designed for serious manufacturing.