Overview
While the protagonist Yossarian is in the hospital during the opening of the novel, he is forced to censor letters written by enlisted men in the same hospital. This soon becomes monotonous and he begins censoring maliciously for pleasure. To these documents that he has ravaged, he signs Washington Irving or, alternatively, Irving Washington. A C.I.D. man, the military's version of a CIA or FBI agent, disguises himself as a patient and goes undercover in Yossarian's hospital, in order to determine the culprit for the over-zealous censorship.
All the other patients soon know the C.I.D. man's identity as he secretly confides in everyone. He further gives away his special status after he refuses to censor any more letters after doing it for a day. When the other patients are scared away by The Texan and leave hospital, the C.I.D. man remains as he has caught pneumonia. Yossarian considers this C.I.D. man as "pretty lucky, because outside the hospital the war was still going on".
Read more about this topic: C.I.D. Investigators