Contents 
THE BROAD VIEW 
History and Problems of Arid Lands Development 
H. L. SHantz 3 
The Role of Science in Man’s Struggle on Arid Lands 
Cuar.es E. KELLocc 26 
The Challenge of Arid Lands Research and Development for the 
Benefit of Mankind 
B. T. Dickson 47 
VARIA BIEIDY AND PREDICTABILITY OF WATER SUPPLY 
Climatology in Arid Zone Research 
C. W. THORNTHWAITE 67 
Water Resources in Arid Regions 
J. TrxeRont 85 
Data and Understanding 
Luna B. LEopotp 114 
Variability and Predictability of Water Supply 
Frank DIxey 121 
Fluctuations and Variability in Mexican Rainfall 
C. C. WaLLEN 141 
Beneficial Use of Water in Arid Lands 
Joun H. Dorrou, Jr. 156 
Geochronology as an Aid to Study of Arid Lands 
Tera L. SMILEY 161 
Summary Statement 
ReeEp W. BalLey 72 
BETIER USE OF PRESENT RESOURCES 
GRAZING RESOURCES 
R. O. WuyTe 179 
Water Resources 
L. N. McCLetian 18g 
Geography’s Contribution to the Better Use of Resources 
Hiicarpb O’REILLY STERNBERG 200 
Agricultural Use of Water under Saline Conditions 
L. A. RicHarps 221 
