Book excerpt: This practical guide covers the commonly used detection methods for seed-transmitted viruses and viroids that affect both tropical and temperate crops. It contains 25 complete step-by-step procedures for biological, serological and molecular techniques to detect and identify such viruses. Combining helpful practical notes with more detailed explanations of the principles behind the techniques, the book describes the general characteristics of seed-transmitted viral diseases and discusses outlines for the organization and interpretation of seed health assays. The techniques reviewed are also applicable to non-seed-transmitted viral agents.