K.D. Magill, Jr., An Interview with John Isbell (web)
Melvin Henriksen, John Isbell 1931-2005 Obituary (web)
F. W. Lawvere, John Isbell’s Adequate Subcategories (web)
Introducing the notion that came to be known as Isbell duality (and discussing foundations for category theory via a kind of Grothendieck universes):
John Isbell, Structure of categories, Bulletin of the American Mathematical Society 72 (1966), 619-655. [[euclid:1183528163](http://projecteuclid.org/euclid.bams/1183528163), ams:1966-72-04/S0002-9904-1966-11541-0]
John Isbell, Normal completions of categories, Reports of the Midwest Category Seminar, 47, Springer (1967) 110-155 [[doi:10.1007/BFb0074302](https://doi.org/10.1007/BFb0074302)]
On the theory of locales (and introducing that term):
John Isbell, General functorial semantics, I, American Journal of Mathematics 94.2 (1972) 535-596 [[doi:10.2307/2374638](https://doi.org/10.2307/2374638), jstor:2374638]
John Isbell, Top and its adjoint relatives, General Topology and Its Relations to Modern Analysis and Algebra (1971) 143-154 [[eudml:221076](https://eudml.org/doc/221076)]