Air Force Handbook 1, Airman (1 October 2015), and the 2015 (Testing to SMSgt) Study Guide, are appropriate study reference materials for the 2018 E-8 promotion cycle starting with the 1-14 December 2017 testing window.
The 2015 Study Guide for enlisted promotion testing to E-8 is available for download here at the AFH 1 Enlisted Promotion Study Guides homepage:
click on DOWNLOADABLE STUDY GUIDES
select AFH 1 (Study Guides) v2015
select Testing to SMSgt
Note: use the MKTS associated with the 2015 AFH 1 Study Guide.
For those studying for next year (the 2019 E-8 promotion cycle):
Download the study guide by right clicking with your mouse on the image below and choosing "save target as" or "save link as"
Air Force Handbook 1, Airman, is the source document for all enlisted promotion study guides. Enlisted promotion study guides contain content that is used as study reference material, and is the same material used to develop the Promotion Fitness (PFE) and USAF Supervisory (USAFSE) examinations. Information in the study guides is tailored to only include MKTS applicable information for promotion to 'the next grade'.
Note: Be sure to refer to the Enlisted Promotion References and Requirements Catalog (EPRRC) for the correct PFE, USAFSE, and SKT study reference materials for upcoming testing cycles: https://www.omsq.af.mil/index.htm.