PREFACE v 
Mexico Institute of Mining and Technology graciously enter- 
tained the Conference. 
The program centered upon those areas of investigation where 
prediction of the future currently must be based upon insufficient 
understanding and data. The state of our knowledge and the need 
for new research are described in the Symposium papers as well 
as the Conference recommendations. They show the difficulty of 
judging the capacity of arid lands resources in the present state of 
knowledge but they also reveal certain ways of looking at the 
problem which bear heavy significance for the future. 
The whole concept of the water budget provides a framework 
of thought in which much detailed analysis in climatology, hy- 
drology, ecology, and geography begins to takeon new importance. 
Simple as it may appear, the concept of selecting, breeding, and 
improving plants and animals for arid conditions rather than 
concentrating upon adjusting the arid environment for plants and 
animals imported from humid areas opens out an enormous field 
for exploration. 
When many disciplines join in viewing an old problem the 
traditional perspectives are challenged, and this is the case with 
views of priorities of water use in arid areas. The relative efficiency 
of various plant covers as water users, the proper allocations of 
water among upstream and downstream uses, and the importance 
of industrial in contrast to agricultural needs are among the 
priorities called into question. Radical revisions in public views 
of water priorities seem in prospect. 
Two other trends in thinking about the future of arid lands 
showed strongly in the conference discussions. One was the 
emphasis placed upon integrated analysis of resources problems on 
a regional basis. In many instances the advantages were recog- 
nized of joining archaeological with hydrologic studies or of link- 
ing botanical with climatological and geomorphic studies. The 
trend is toward a cooperative approach to common problems. 
This does not necessarily mean full integration of basic surveys in 
the field but it does lead to a more nearly unified attack in such 
areas as the Upper Rio Grande basin. 
Second, the natural scientists repeatedly emphasized the im- 
