Nanotechnology will be the realm of most critical engineering.

Gerald Feinberg :
The techniques for nanotechnology were already being developed in 1987. Tunneling microscopy and X-ray holography can be used to visualize objects on an atomic scale. Molecular beam lithography and trapping of individual atoms by laser beams or magnetic fields have been used to move and place atoms as the experimenter desires. These techniques will surely be refined to the point where we become capable of doing engineering on the nanoscale as we can now do on the macroscale. It was this mastery of atoms and molecules which led to many of the most prominent features of the world you now inhabit. 
In 1987 the L. Ron Hubbard Writers of the Future sealed into a time capsule predictions for 2012 made by a number of science fiction writers. The capsule was extracted and opened 25 years later, in 2012.

L Ron Hubbard Writers of the Future time capsule, 1987