Caballeros, Bribones Y Pajaros Egocentricos

Mathematician and combinatorial logician Haskell Curry, in besides being a specialist in systems theory and formal processes, was an avid birdwatcher. Motivated by the memory of the late Professor Curry, Raymond Smullyan chose birds as the combinatorial objects for some of the riddles that appear in this unique work. The reason the author chose combinatorial logic as the central theme of his book was not the existence of multiple practical applications, but its great entertainment potential. Although it is an abstract science considered highly technical, the objects called combinators presented by Smullyan under the guise of truthful knights, lying knaves or talking birds allow introducing fundamental theories of modern logic in a very accessible way for the general public. What better for a book of mysteries and riddles?