There is a German proverb that among four lawyers, there are five different opinions. This is, in some sense, also true of probabilistic reasoning: there is a plurality of competing approaches which the outsider finds hard to oversee. Subjective Bayesianism, interval-valued probabilities, Dempster-Shafer theory, classical statistics, the Principle of Maximum Entropy, Evidential Probability and so on. To the untrained eye, they all appear disparate and sometimes idiosyncratic. While it is hard to judge the degree to which they conflict and cohere, it is even harder to come up with a unifying perspective. Perhaps, it is for that reason that relatively few researchers devote their time to investigating parallels, differences and conflicts between these frameworks-among the notable exceptions, there are Teddy Seidenfeld (1979, 1987) and Isaac Levi (2007). Since these researchers are not any more in the bloom of their youth, it is nice to see that the baton is passed on to the next generation. On not more than 155 pages, Rolf Haenni, Jan-Willem Romeijn, Gregory Wheeler and Jon Williamson make a heroic tour de force through these theories of probabilistic reasoning, with the aim of identifying a unifying overarching framework. The core idea of their book is derived from an analogy with classical first-order logic. There, the central question is the validity of an entailment relation between propositions / 1 ,…,/ N (the premises) and proposition w (the conclusion): / 1 ;. . .; / N w: ð1Þ Probabilistic logics differ from classical logics in that the valuation function maps these propositions not to the binary values ''true'' and ''false'', but to sets X , [0, 1]. The sentence / X is standardly interpreted as ''the probability of / lies in the