A second engrossing chronicle of French colonialism in Africa, by the author of the acclaimed Conquest of Morocco--with perhaps a stronger interpretive thrust. Why, Porch asks, did the French want to occupy the bleak Sahara? His immediate answer is that most of them didn't: even lush Algeria didn't pay, the Sahara had no discernible value. But after France's humiliation in the 1870 Franco-Prussian War, nationalist politicians looked outward--and the Sahara was a vacuum. Rivalry with the British in central Africa fueled dreams of linking up France's North and West African possessions. (For Porch, the economic motive was a very minor one.) The French colonial army was staffed with St. Cyr's misfits and ""hooligans""--who saw in exploration and conquest paths to glory. (They weren't crazed by the sun, they were erratic or unprincipled sorts to begin with.) In the shaky Third Republic's Colonial Party, these officers found support. Then, when expeditions were wiped out by the desert Tuareg, France had to be avenged. If the Sahara couldn't be conquered from the north, it might be conquered from the west. If grimy Timbuktu proved to be a meager prize, there remained the ""mirage"" of Lake Chad. With Lake Chad seized, the oasis of the Tua, crossroads of the Sahara, beckoned. Was the Tua, once conquered, to be left with a mere token garrison? An ingenious, astute colonial officer--unusual in every respect--developed, in the Saharaians, a mobile, camel-mounted force of native Chaama Arabs (and heterogeneous auxiliaries) which finally, in 1905, brought the Tuareg to seek peace. Porch introduces this intricate tale of daring, idiocy, chicanery, and plain butchery (on both sides) with considerable demythologizing--of the Tuareg, for one. Yet his epilogue is a quiet lament for the extinction of desert life with European occupation. The conquest of the Sahara is not less stirring for being seen in truer colors.