The ST BOOK (later version portable STE), vastly more portable than the STacy, but sacrificing several features in order to achieve this - notably the backlight, and internal floppy disc drive. It was first released in 1991.
The screen is highly reflective, it is fixed to the 640x400 1-bit mono mode and no external video port was provided. For its limitations, it gained some popularity as being the most utterly portable 'real' computer of the day (slim, light, quiet, reliable, and with a long battery life, even by today's standards for all 5).
In its features comparable to Macintosh PowerBook 100 series.