This volume, Surface Water Resources of the Virgin and Fallow Land Development Region, contains information on the rivers, intermittent waterways, and lakes located within North Kazakhstan Oblast of the Kazakh Soviet Socialist Republic. The data on surface waters presented in the book are based primarily on materials collected during specialized investigations conducted by expeditions of the State Hydrological Institute between 1955 and 1957, as well as on observations from the network of stations and monitoring posts operated by the Hydrometeorological Service of the Kazakh Soviet Socialist Republic and other agencies. Like the four previously published volumes devoted to Akmola, Kustanai, Kokchetav, and Pavlodar oblasts, this work is intended as a practical reference manual designed primarily for hydraulic engineering and water-management planning organizations. Because long-term observational records for watercourses in North Kazakhstan Oblast (with the exception of the Ishim River) are lacking, calculations of surface runoff were carried out by methods similar to those applied in Pavlodar Oblast. Unlike the approach used in the other oblasts of Northern Kazakhstan, a water-balance methodology was employed, whereby runoff from the watershed surface was treated as a component of the water balance of natural water bodies (lakes). In view of the generally insufficient level of hydrological investigation within the study area, the hydrological characteristics presented in this volume, particularly runoff values, should be regarded as approximate. In discussing the methodological basis for calculating hydrological parameters, certain topics that had already been examined in detail in earlier volumes, such as lake water balance, water withdrawal calculations, and the influence of land cultivation on runoff, are treated in abbreviated form. Owing to the natural characteristics of North Kazakhstan Oblast and the relatively limited level of surface-water research, the structure of this volume is similar to that of Volume IV (Pavlodar Oblast) and differs from the three earlier published volumes (Volumes II-III). This publication is the result of the work of numerous staff members of the State Hydrological Institute, both during field investigations and in the compilation and analysis of materials within the Institute. Participants in the field expeditions included A. P. Bogoroditsky and I. A. Maksimov (heads of the North Kazakhstan Expedition); section leaders A. P. Braslavsky, P. P. Voronkov, A. A. Pukin, I. Z. Samblenko, and O. A. Spengler; team leaders V. V. Dementyev and I. N. Obraztsov; engineers L. A. Korolyova and V. V. Pokrovsky; technicians L. I. Maksimova and N. N. Sivakov; and observers S. D. Vinnikov, Yu. M. Koledenko, and others. Part of the field hydrological survey work was carried out by a team led by G. D. Eirikh of the Omsk Hydrometeorological Service. The development of the methodological foundations of the monograph and the synthesis of the materials presented in it were accomplished primarily by staff members of the Runoff Department of the State Hydrological Institute under the direction of K. P. Voskresensky and M. S. Protasyev. The individual chapters of the monograph were prepared by the following contributors: Chapters 1 and 4: A. G. Kovzel, Candidate of Technical Sciences; Chapter 2: I. A. Maksimov, Candidate of Geographical Sciences; Chapter 3: Sections 1 and 4: A. G. Kovzel and O. A. Spengler (snow reserves in various landscape types); Sections 2 and 6: I. A. Maksimov; Section 3: A. G. Kovzel and engineer I. N. Obraztsov (lake water balance), and A. P. Braslavsky (calculation of potential water withdrawals from lakes and reservoirs, with the participation of M. L. Berkut); Section 5: A. G. Kovzel and I. N. Obraztsov; Chapter 5: Junior Researcher K. N. Lisitsyna; Chapter 6: A. P. Braslavsky (temperature regime); A. G. Kovzel (ice conditions); Chapter 7: P. P. Voronkov, Doctor of Geographical Sciences; Chapter 8: I. A. Maksimov, V. V. Dementyev, I. N. Obraztsov, G. D. Eirikh, V. N. Ternova (hydrological descriptions of individual water bodies), with the participation of engineer V. V. Vasilyeva and junior researcher N. I. Mikiy; Chapter 9: I. A. Maksimov and engineer G. S. Pushkarev (Water Management Department of the Executive Committee of North Kazakhstan Oblast). A considerable amount of work related to the collection and organization of data was carried out by engineers G. V. Ardasheva and I. N. Obraztsov, together with senior technician O. S. Shafkina. The determination of watershed areas for rivers and lakes from topographic maps was performed by the Cartography Department under the direction of E. P. Senkov. Calculations based on aerial-photographic materials were carried out by junior researcher S. I. Pinkovsky under the supervision of A. A. Pukin, Candidate of Technical Sciences. The maps and illustrations were prepared by the Cartographic Group of the Computing and Consulting Division of the State Hydrological Institute under the leadership of V. P. Semyenchukov. Publication preparation for this volume was completed by L. F. Manonin. Overall supervision of the field investigations and preparation of the monograph was provided by V. A. Uryvayev, Director of the State Hydrological Institute, and his deputy, A. I. Chebotaryov. Editorial review and evaluation of the volume were conducted by an editorial board consisting of: V. A. Uryvayev, Candidate of Technical Sciences (Editor-in-Chief); K. P. Voskresensky, Candidate of Geographical Sciences (Chapter 2, Chapter 3 Section 4, and Chapter 5); A. P. Domanitsky, Candidate of Geographical Sciences (Chapter 8); M. S. Protasyev, Candidate of Geographical Sciences (Chapter 1, Chapter 3 Sections 1 and 2, and Chapter 9); D. L. Sokolovsky, Doctor of Technical Sciences (Chapter 4); A. I. Chebotaryov, Candidate of Technical Sciences (Chapter 3 Sections 3, 5, and 6, and Chapter 6).