Recent theoretical results are highlighted that illustrate some of the interesting phenomena associated with magnetic domain boundary walls. Two problems will be discussed: dynamics associated with domain wall propagation, and effects related to spin transport through domain walls. For the first problem, an example of wall interaction and motion through a random potential will be discussed with reference to the general problem of roughening transitions. Images of domain dynamics in thin films of ion irradiated Co reveal a de-roughening transition associated with long range magnetostatic interactions between pairs of domain walls. A scaling theory of this transition is described in which a curious type of dynamic hysteresis can occur. For the second problem, results from calculations of ballistic charge and spin transport through domain boundary walls are discussed in terms of an effective circuit model. (C) 2007 Elsevier B.V. All rights reserved.