Excerpts from the Preface: This is Part IV of the third of a series of indexes or source books of agricultural statistics issued by the Library of the United States Bureau of Agricultural Economics. It is issued in cooperation with the College of Agriculture of the University of California. This Index to the state official and unofficial sources of agricultural statistics of the state of California was undertaken with the idea of issuing it in one volume as were the Alabama and Oklahoma indexes. When the indexing of the collected references was finished it was realized that it would be impossible to publish the Index in one volume because of its size, so it was decided to issue it in five parts. Part I includes the fruit, vegetable and nut crops of the state. Part II includes the crops other than fruits, vegetables and nuts. Part III includes livestock and livestock products. Part IV, which is the present volume, includes land, farm property, labor, Delhi and Durham state land settlements, irrigation, and related subjects. Part V is a Guide to Some Unofficial Sources of California Agricultural Statistics and was compiled under the direction of Mrs. M. J. Abbott, Agricultural Reference Librarian, University of California Library. The first four parts of the index include references to all state official sources of agricultural statistics that the compilers could find from the time of beginning the index in 1925 through December 1927.