The State of Preschool 2018 is the 16th edition of NIEER's annual report tracking state-funded preschool access, resources, and quality. Since 2002, the preschool landscape has changed in many ways; and in others, it has remained the same -- highlighting the need for a renewed commitment to progress. Since 2002 when NIEER began tracking preschool enrollment, states have added more than 882,000 seats in state-funded preschool, mostly for four-year-olds. Progress has been uneven both across states and over time. The annual change in the number of children served in state-funded preschool has varied from an increase of nearly 140,000 children between 2004-2005 and 2005-2006--a nearly 18% jump--to a decrease between 2011-2012 and 2012-2013. (author abstract)