Graham Sellers, API lead on the Vulkan specification, is AMD Software Architect and Engineering Fellow. Sellers represents AMD at the OpenGL ARB, has actively contributed to the core Vulkan and OpenGL specs and extensions, and holds several graphics and image processing patents. He coauthored OpenGL® Programming Guide, Ninth Edition. Contributing author John Kessenich is language lead on the Vulkan specification and is Senior Compiler Architect at LunarG Inc. He been active in OpenGL, GLSL, Vulkan, and SPIR-V development in the OpenGL ARB and in Khronos since 1999. Kessenich created SPIR-V and is its specification editor. As GLSL specification editor, he creates shader compiler tools and translators for improving portability.