Background and context: What is the sharing economy and how can it be governed? -- Platform work: implications for employment relations and the broader labour market -- Bibliography -- Preface -- Concluding remarks – how to bridge the knowledge gap? -- Introduction -- Summary.

We study sequential bargaining between two unions and a single firm. Parties bargain bilaterally and efficiently (over wage and employment). The unions' workforces can be substitutable ("tariff competition") or complementary ("tariff plurality" or "craft unionism"). If unions are substitutable,...