Brief though it is, _Priniciples_ manages to cover not only the usual topics (sentential calculus, first-order predicate calculus, completeness, decidability), but also: the monadic predicate calculus in relation to Aristotelian logic; second-order logic; set theory and the Fregean concept of number; and the theory of types (logics of higher order). You might say that Hilbert covers the same ground in 160 pages that Russell and Whitehead labor over for 3 volumes. The bottom line: a treat for anyone interested in logic, especially in the period from Frege to Godel.