In an effort to protect its market share from such challengers as Amazon and Google, Apple Inc is releasing its own version of a smaller sized tablet device, the iPad Mini.

The iPad Mini is the rampart defending Apple’s control of the market on extra-portable personal computing devices just as Amazon’s Kindle and Google’s Nexus 7 are beginning to make inroads into that market.

The smaller device is considerably less expensive then Apple’s popular best-seller, the iPad 10-inch full-sized model, and is the first device added to Apple’s compact portfolio since the reins of leadership of Apple was handed over to Tim Cook, who took over from Steve Jobs just before his death.

"Apple sensed early that they had a real winner with the iPad and that has proven to be correct," said Lars Albright, co-founder of mobile advertising startup SessionM and a former Apple ad executive.

"They have a large market share, and to protect that market share they have got to be innovative," he added.

The Apple iPad Mini will be unveiled today, Tuesday, October 23,  at a “by invitation only” event scheduled to begin at 10am in San Jose, California.