The idea of Laptop came as early as late 1960 with the Dynabook, but this Tablet PC was mainly for children.
It was in the early 80s that the first truly portable computer was developed, the Osborne 1 did not have any batteries, (it had to be plugged in), but at least the data and computer could be transported.
A year latter Epson announced the first truly portable computer with a nickel battery. The Epson was more like an advanced calculator with only 80 characters displayed at any one time.
In 1984 the Gavilan SC and the Sharp PC-500 entered the market, with the Gavilan been the first to introduce the concept of the laptop, (and a basic pointing device). By the end of the 1980s, many laptop manufacturers had developed fairly similar machines. All about ranging from the size of an A4 page to an A3.
By the beginning of the 1990s, the look and feel of the laptop was defined by the Apple computers, (built in trackball, keyboard, and Palm rest). Not to be outdone the IBM Thinkpad 700C introduced the TrackPoint a year later.
Since the mid-90's only technology has improved the laptop computers. Longer lasting batteries, as well as huge hard drives, now make the Laptop a serious challenger for the desktop.