There are claims made by some researchers and consultancies – among others – that there are fundamental differences between generations (e.g. “Baby Boomers” and “Millennials”) in terms of, for example, personality and preferences, motivation, and work values. However, these claims are often presented with more confidence than is warranted, given that the evidence is mixed, and effect sizes often small. This chapter critically explores the evidence, but also questions the “reality” of generational categories often used (e.g. “Baby Boomers”). Key issues explored in this chapter include the implications of generational cut-off points, assumptions of experiences and characteristics that are both shared within and unique to particular generations, and the role played by, and impact of, stereotypes. It is argued that organisational policy should not be informed by claims made about generations, e.g. what members of a particular generation want. Practice should be informed by better quality bodies of evidence, e.g. relating to the design of work or the use of rewards. If generational research is to provide useful insights, different research approaches are necessary. This is a preprint of a book chapter in search of a permanent home. I welcome suggestions on potential homes for this chapter, as well as feedback on the chapter itself. Readers are welcome to cite this chapter in its present form.