Disguise is not advisable. Except in special areas, let it be clearly known that you are British officer and a Christian. At the same time, if you can wear Arab kit when with the tribes, you will acquire their trust and intimacy to a degree impossible in uniform. It is, however, dangerous and difficult. They make no special allowances for your when you dress like them. Breaches of etiquette not charged against a foreigner are not condoned to you in Arab clothes. You will be like an actor in a foreign theatre, playing a part day and night for months, without rest, and for an anxious stake. Complete success, which is when the Arabs forget your strangeness and speak naturally before you, counting you as one of themselves, is perhaps only attainable in character: while half-success (all that most of us will strive for; the other costs too much) is easier to win in British things, and you yourself will last longer, physically and mentally, in the comfort that they mean. Also then the Turks will not hang you when you are caught.
-T.E. Lawrence in his “Twenty-seven Articles,” 1917