This manual brings together information on all phases of seed handling and presents the results of more than 20 years of studies. Forest Service field personnel at several experiment stations and regional offices furnished a backlog of source material for treatments of individual genera. The manual consists of two main parts. Part 1 formulates general principles on the various phases of seed handling from formation of the seed to sowing. Part 2, which forms the larger part of the manual, provides relatively detailed but concise information for 444 species and varieties of trees and shrubs; this includes data on distribution and use, discussions of seeding habits, methods of seed collection, extraction and storage, seed germination, and nursery and field practice.