An extremely detailed atlas similar to the Sanborn insurance maps; updates pasted in and on versos of some original map plates (dates of updates not known). Full color key is explained in legends on plates. Baist first published the Los Angeles atlas in 1905 with 26 maps plus index; subsequent editions appeared in 1910 (34 maps plus index), 1914 (44 maps plus index), 1921 (this copy, 49 maps plus index) and 1923 (49 maps plus index). The period after World War I was a time of real estate expansion and development, hence the many updates in this 1921 edition. The 1921 edition is the first edition to include the five San Fernando Valley maps. 1921 date is original date of publication.