In contrast to most science fiction franchises, toys are the core of the Transformers brand, its original reason for being. Most Transformers fiction exists to showcase, spotlight, promote, and in general to sell toys. Merchandise and other non-transforming "artifacts" also generally exist in support of the toy lines.
Transformers toys are generally created and marketed as part of a particular "franchise" (i.e. Beast Wars, Armada, the retroactively-named Generation 1 etc.), a whole merchandising family with associated characters and fiction. However, this article deals with the physical toys themselves, separate from their representation as fictional characters.
Since the brand debuted in 1984, innumerable Transformer toys have been designed, manufactured and marketed. An exact count is difficult due to the varied nature of the toys (for example, does a Headmaster robot and its partner mini-figure count as one Transformer or two? What about minor retools and running changes?) But even conservative estimates by collectors tend to run into the low thousands.
Most Transformers are designed as a joint venture between Hasbro in America, and TakaraTomy(previously Takara) in Japan. Hasbro typically provides concepts and artistic direction, while Takara(Tomy) handles the engineering tasks of turning the designs into working physical objects. This division of labor is not cut-and-dried, however; the process involves a great deal of back-and-forth communication between the two companies, with staff members from both working in close conjunction and corresponding on a daily basis. The teams travel overseas several times a year to meet in person, alternating between Japan and Rhode Island. The relationship has grown closer and more intense over the years; the two companies now plan their futures together, compromising along the way to meet the differing requirements of their target markets; this includes not only to toy designs, but associated storylines as well. 
The toy design process begins with a range of character types and possible alternate modes. In the days of Beast Wars, for example, a range of about 100 animal forms was considered.
Nearly all Transformers toys have a minimum of two forms, most commonly a humanoid "robot" form and an alternate mode. This means that even a fairly simple Transformer is much more complex than the typical action figure. Multiple alternate modes, articulation, and complex transformations can multiply this many times over. TakaraTomy works out the transformation schemes; as of 2002, Takara still did this on paper. Hasbro would then overlay their detailing designs on the drawings. The entire process of taking a toy from concept to finished, mass-produced product takes approximately one year.
Because of their worldwide marketing, Transformers must be designed to meet many widely-varying safety laws. This often results in certain limitations, and even changes being made before toys are sold in the highly litigious United States of America compared to their Japanese releases.
On the MUX, Hasbro sells toys based on both existing and made-up Transformers. Rumor has it Hubcap gets a cut of the Autobot designs, but no one has produced proof.
| This page uses content from Teletraan I: The Transformers Wiki. The original article was at Toy.