This book presents the methodology and results of a study designed to determine the feasibility of implementation of some of the most popular, widely available and relatively cheap machine translation systems into translation processes carried out in the English - Polish language pair. A set of outputs provided by DeepL Translator, Google Neural Machine Translation System and Microsoft Translator engines was collected and processed together with translated and post-edited segments produced by a group of Polish translators. The data were then analyzed with the use of various MT evaluation metrics to determine whether the quality of the outputs and amount of post-editing effort was adequate enough to enable efficient implementation of the analyzed engines into the professional environment.