This data collection, the first edition in the World Handbook series, comprises interval-level social, political, economic, and demographic indicators for 141 countries in the period 1961-1963. Information is provided for the size of the country, the number of years independent, total population, population per square kilometer, gross national product (GNP), gross capital formation as a percentage of the GNP, government revenue and expenditure, foreign trade, employment in industry and in agriculture, degree and annual increase of urbanization, and voting characteristics. Other variables provide information on security, public enterprise, military personnel and expenditure on defense, domestic group violence, and votes in national elections for political parties such as the Communist and Socialist parties, religious parties, and noncommunist secular parties as percentage of total votes. Other variables provide information on population characteristics such as the number of births and deaths per 1,000, live births per 1,000, life expectancy at birth, income distribution, percentage of population of working age, Roman Catholics, Christians, and Moslems as a percentage of the population, immigrants and emigrants per 1,000 population, percentage of literate population aged 15 and above, enrollment in primary and secondary schools, index of achievement motivation, marriages per 1,000 population aged 15-44, and inhabitants per physician and per hospital bed. Additional variables provide information on daily newspaper circulation, radios and televisions owned, cinema attendance per 1,000 population, private consumption, and the distribution of agricultural land.