Status of the Twist Measurement of the Muon Decay Parameter P$_{\mu}\xi$

Muon decay, a purely leptonic decay, is a relatively simple interaction to study when looking for physics not explained by the standard Vector minus Axial Vector (V-A) theory of electroweak interactions. The TWIST spectrometer measures the doubly differential spectrum of decay positrons for a wide range in reduced energy and angle between muon and decay positron momentum. By measuring a large part of muon decay spectrum, TWIST is sensitive to the exact shape of the decay spectrum, and can simultaneously measure three of the muon decay parameters with a high degree of accuracy. I will review the status of the TWIST experiment, and physics related to the muon decay parameter P$_{\mu}\xi$. TWIST will measure P$_{\mu}\xi$ by about an order of magnitude better than previous direct measurements. The status of analysis of systematic uncertainties in the measurement of P$_{\mu}\xi$ is presented.