  Distributions measured in high energy physics experiments are usually
distorted and/or transformed by various detector effects. A regularization
method for unfolding these distributions is re-formulated in terms of the
Singular Value Decomposition (SVD) of the response matrix. A relatively simple,
yet quite efficient unfolding procedure is explained in detail. The concise
linear algorithm results in a straightforward implementation with full error
propagation, including the complete covariance matrix and its inverse. Several
improvements upon widely used procedures are proposed, and recommendations are
given how to simplify the task by the proper choice of the matrix. Ways of
determining the optimal value of the regularization parameter are suggested and
discussed, and several examples illustrating the use of the method are
presented.
