Our purpose in writing this monograph is twofold. On the one hand, we want to collect in one place many of the recent results on the exist- ence and asymptotic behavior of solutions of certain classes of singularly perturbed nonlinear boundary value problems. On the other, we hope to raise along the way a number of questions for further study, mostly ques- tions we ourselves are unable to answer. The presentation involves a study of both scalar and vector boundary value problems for ordinary dif- ferential equations, by means of the consistent use of differential in- equality techniques. Our...