Gift ideas -- choicest new books for the holidays; Muslim world in vivid photos; The World of Allah, by David Douglas Duncan. Boston: Houghton Mifflin Company. 280 pp. $35.

Like many a Westerner, photographer Duncan - a self-styled ''nomad from Missouri'' - found life among the Muslims an experience of humanity and hospitality far different from today's headlines of zealotry and strife. Here, roaming from Morocco to Pakistan, he records a ''wanderer's romance'' as striking for its pictorial art as its representation of places and people. Only a rare oil derrick towering over a caravan or a freighter behind a fisherman's ancient nets hint at today's context for the traditional ways of shepherds, spinners, potters, and worshippers that Duncan captures as securely as the modern iconography in his famed Picasso photos. Gleaming reflections, gritty textures, carven silhouettes, mosaics with every tessera distinct - these are a few of the elements that surround the eloquent faces of Islam from nomad Duncan's file.