[1] In 1944 he published a seminal work on countercurrent distribution, which became an important separation technique.
[2] Craig continued to develop the theory, improve the apparatus and devise new applications of the countercurrent distribution into the 1970s.
[4] In 1950, Craig invented the rotary evaporator which is a necessary equipment in most chemical labs.
[5][6] He also invented the Craig tube, an apparatus used in small-scale chemistry, in particular for recrystallization.
[8] He was the recipient of the 1963 Albert Lasker Award for Basic Medical Research.