Worker classification is the single legal question that decides whether a person earns a minimum wage, collects overtime, participates in a retirement plan, can sue for discrimination, can unionize, and whether the company writing the checks owes years of back payroll taxes. This UpLaw guide explains why there is no unified answer: the Fair Labor Standards Act uses a broad "suffer or permit" economic-reality test that the Department of Labor has rewritten twice in three years; the IRS applies a common-law control test rooted in Rev. Rul. 87-41 and softened by Section 530 relief; California and a growing number of states impose the presumptive ABC test after Dynamex and AB5; the NLRA and ERISA each run their own common-law analyses; and copyright and patent law add an ownership overlay that can strip a company of the very work it paid for. It traces what the leading cases actually held, from Rutherford Food and CCNV v. Reid through Nationwide v. Darden, Vizcaino v. Microsoft, and the gig-economy fights that produced Proposition 22. It maps joint-employment exposure for staffing agencies, franchisors, and platforms, and it prices out the cost of getting classification wrong: back wages, liquidated damages, employer FICA, benefit restoration, statutory penalties, and class and collective exposure. It closes with a practical program for structuring a genuine contractor relationship, papering it correctly, auditing an existing workforce, and remediating misclassification without turning a compliance project into a lawsuit.