The U.S. Department of Labor posts information about the Federal garnishment law.
Garnishment laws for all 50 states are summarized by BCS Alliance.com, the CCH Consumer Credit Guide and West's Guide to Employment Law and Regulation; double-check the summaries with the relevant state statutory codes. Or skip the summaries and go directly to the codes.
Garnishment is discussed in the Vicki Lambert's Garnishment: A Practical Guide (CCH), Joan Garrett's The Law of Attachment & Garnishment (Oceana Publications), Amorette Nelson Bryant's Complete Guide to Federal and State Garnishment,
the Employer's Guide to Garnishment (RIA) and Robert Hobbs' Fair Debt Collection (National Consumer Law Center).