Demography is the scientific study of human populations with respect to their size, distribution, the structure and population change over time. Thus, the study of birth intervals is important in understanding fertility dynamics. Birth intervals have been observed to influence the tempo and pace of child bearing and hence the resulting fertility level in any given society. This book describes methods used by demographers to analyse birth interval data. It covers in details trends of birth intervals in Kenya and how they are influenced by socio-economic, cultural and demographic factors. The book covers materials taught in introductory courses in demographic analysis and also includes more advanced topics such as parity progression ratios, survival life tables and hazards models. This book is intended for use by professional demographers, sociologists, anthropologists, economists, health scientists, epidemiologists, psychologists, political scientists, educationists, students of demography, and policy makers.