Published online by Cambridge University Press: 12 April 2016
The use of interstellar polarization as a measurement tool for dust or magnetic field presents practical difficulties (dust and magnetic field configurations inextricably mixed up; limited number of suitable stars). This general rule applies even more in the local environment, for which the polarizations are small and the influence of errors of observation changes in character. Because of this, the use of polarimetry and the design of polarimetric observing programmes for the local interstellar medium must be approached with even greater care than in the general case. I propose in this review to amplify this point, so that the reader can judge for himself to what extent he can use published results and can also, given the opportunity and instrumentation, design an observing programme that will really pay off.