The Survey of Adult Skills: Reader’s Companion, Second Edition describes the design and methodology of the survey and its relationship to other international assessments of young students and adults. It is a companion volume to Skills Matter: Further Results from the Survey of Adult Skills. Skills Matter reports results from the 24 countries and regions that participated in the first round of the survey in 2011-12 (first published in OECD Skills Outlook 2013: First Results from the Survey of Adult Skills) and from the nine additional countries that participated in the second round in 2014-15 (Chile, Greece, Indonesia [Jakarta], Israel, Lithuania, New Zealand, Singapore, Slovenia and Turkey).