The manual that accompanies these appendices was produced to familiarize data users with the design, and the procedures followed for data collection and processing, in the base year and first follow-up of the High School Longitudinal Study of 2009 (HSLS:09), with emphasis on the first follow-up. It also provides the necessary documentation for use of the public-use data files and information that will be helpful to analysts in accessing and understanding the restricted-use files. The following appendices are included in this document: (1) First Follow-up Questionnaires; (2) HSLS:09 First Follow-up Mathematics Assessment Item Characteristics; (3) Glossary of Terms; (4) Data Collection Materials: Contacting and Permission Forms; (5) Documentation for Composite Variables; (6) Standard Errors and Design Effects; (7) Unit and Item Nonresponse Bias Analyses; (8) Imputation Details; (9) Hard Copy Codebooks: Student and School; (10) Comparison of Public- and Restricted-use Files; (11) Variable List for HSLS:09 Electronic Codebook (ECB); (12) High School Longitudinal Study of 2009 (HSLS:09) First Follow-Up Field Test Report; (13) Field Test Report Appendixes; (14) First Follow-up Critical Items; and (15) Questionnaire Flow Charts. [For the full report, "High School Longitudinal Study of 2009 (HSLS:09) Base Year to First Follow-Up Data File Documentation. NCES 2014-361," see ED565643.]