deepened dramatically following the observation that strings with large quantum numbers can be mapped to certain subsets of operators in the gauge theory [@Berenstein:2002jq; @Gubser:2002tv]. Direct progress has been made in testing the correspondence perturbatively by comparing anomalous dimensions of gauge theory operators and energies of classical and quantum corrected string solitons [@Frolov:2002av; @Frolov:2003tu; @Beisert:2003xu; @Frolov:2003xy; @Callan:2003xr; @Beisert:2003ea; @Kruczenski:2003gt; @Kruczenski:2004kw; @Callan:2004uv]. For reviews see [@Tseytlin:2003ii; @Beisert:2004yq; @Tseytlin:2004xa; @Zarembo:2004hp; @Swanson:2005wz; @Plefka:2005bk].

These comparisons have used and motivated much progress in computing gauge theory anomalous dimensions. Beginning with the proof of one-loop integrability in the ${{\mathfrak{so}}}(6)$ (scalar) sector[^1] [@Minahan:2002ve], computations of anomalous dimensions in planar $\mathcal{N}$ = 4 SYM have been greatly simplified by mapping single-trace gauge theory operators to states of integrable closed spin chains. This mapping allows the use of a Bethe ansatz. In [@Beisert:2003yb], integrability of the complete one-loop planar gauge theory was proven, and the corresponding Bethe ansatz was presented. After evidence of integrability was obtained via higher-loop computations of the dilatation generator in compact sectors [@Beisert:2003tq; @Beisert:2003ys], higher-loop Bethe ansätze were proposed at various orders and sectors [@Serban:2004jf; @Beisert:2004hm; @Staudacher:2004tk]. This line of research culminated with a proposal for the all-loop asymptotic ${{\mathfrak{psu}}}(2,2|4)$ Bethe ansatz [@Beisert:2005fw]. A 