Although chaotic behaviour had often been observed numerically earlier,
the first mathematical proof of the existence, with positive probability
(persistence) of strange attractors was given by Benedicks and Carleson
for the Henon family, at the beginning of 1990's. Later, Mora and Viana
demonstrated that a strange attractor is also persistent in generic
one-parameter families of diffeomorphims on a surface which unfolds
homoclinic tangency. This book is about the persistence of any number of
strange attractors in saddle-focus connections. The coexistence and
persistence of any number of strange attractors in a simple
three-dimensional scenario are proved, as well as the fact that
infinitely many of them exist simultaneously.