The SEGA Saturn was SEGA's full fledged dive into 32 bit gaming after the failed 32x upgrade for the Genesis. During the early days of development, SEGA was approached by Sony and SGI to pitch their concepts. As we all know, Sony ended up going it's own route, and SGI supplied the hardware for the N64. SEGA decided to go it's own with a dual CPU architecture with a total of 8 internal processors.
The reason behind the dual SH-2 CPU design was to help the Saturn compete with Sony in the 3D realm. Publicly, the reasoning behind the 8 processors, however, was to help the Saturn bring home what Sega had planned for the next year in the arcades. The Saturn's ultimate goal was to bring the arcade home. In other words, straight ports, not translations. However, this was not the case. Sega's hardware proved to be entirely to difficult to program for, as developers were not comfortable trying to take advantage of all of the processors designated for graphics.
The Saturn was initially going to be a 2D powerhouse. The pixel pushing power was unseen at the time. The PlayStation, being designed with 3D first mentality couldn't come close to what the Saturn could do. Even the best N64 2D game was not on par with the Saturn's 2D games (IMO). Interestingly, the Saturn could do better 3D games than the PlayStation, but back to the development issues...the system never got to see the full fledged capabilities that the system had inside of it. (There has been much confusion regarding the polygon pushing power of the two consoles, but it turns out that the Saturn was actually pretty impressive. If only the devs would have caught on!)
The Saturn was accused of not having a very good library of games, leading to its ultimate demise. However, that is not true. The Saturn received a very large selection of titles that were fun, and engaging to play. It is agreed upon, though, that the lack of a Sonic game didn't help the Saturn. It gave the appearance that SEGA didn't put much faith in the console to have it "carry" its mascot.
The SEGA Saturn was officially discontinued in North America in 1998, and in Japan in 2000.