Citadel by Algis Budrys

Marlowe was obese. He sat behind his desk like a tuskless sea lion crouched behind a rock, and his cheeks merged into jowls and obliterated his neck. His desk was built specially, so that he could get his thighs under it. His office chair was heavier and wider by far than any standard size, its casters rolling on a special composition base that had been laid down over the carpeting, for Marlowe's weight would have cut any ordinary rug to shreds. His jacket stretched like pliofilm to enclose the bulk of his stooped shoulders, and his eyes surveyed his world behind the battlemented heaviness of the puffing flesh that filled their sockets.

A bulb flickered on his interphone set, and Marlowe shot a glance at the switch beneath it.