Rainer Walter "Ray" Guillery FRS (28 August 1929 – 7 April 2017) [1] was a British physiologist and neuroanatomist.

[2] He is best known for his discovery that in Siamese cats with certain genotypes of the albino gene, the wiring of the optic chiasm is disrupted, with less of the nerve-crossing than is normal.

[1] He began his education as a medical student at University College London (UCL) in 1948.

In 1977, he moved to the University of Chicago to lead another new graduate neuroscience programme.

[2][4] He was then subsequently a professor emeritus of anatomy at the University of Wisconsin Medical School[5] and, as of 2010[update], an honorary emeritus research fellow at the Anatomical Neuropharmacology Unit at Oxford.