Are we in the midst of a financial bubble? Do the current valuations of the electronic vehicle stocks or their SPACs make you raise an eyebrow? The trouble with bubbles is that they are hard to spot from within, and much easier to define and analyze after the fact.  In their new book, Boom and Bust: A Global History of Financial Bubbles (Cambridge University Press, 2020), William Quinn and John D. Turner analyze past instances of extreme speculation to come up with a typology of the phenomenon. Using what they call the Bubble Triangle of Marketability, Easy Money, and overt Speculation, they have created a tool for financial economists, and the rest of us, to judge what makes a bubble and what makes it pop. Given the unusual nature of the capital markets at the present time, you will want to be familiar with their analysis as you view your own investments.Daniel Peris is Senior Vice President at Federated Hermes in Pittsburgh. He can be reached at DanielxPeris@gmail.com or via Twitter @HistoryInvestor. His History and Investing blog and Keep Calm & Carry On Investing podcast are at https://strategicdividendinvestor.com