The best replacement for executive summary is abstract.

The best alternatives to executive summary are rated as following:
★★★★★  abstract
★★★★★  introduction
★★  conclusion
★★  synopsis
★★  mission statement
★★  company summary
★  overview
★  cover letter
★  business plan
★  table of contents first
★  introduction first
  project charter
  preface
  table of contents
  introduction difference
  white paper
  table of contents come first
  conclusions
  letter of transmittal

Your alternative for executive summary is not listed? Suggest!
Speaking about executive summary, one probably shouldn't forget about report.

Other search terms related to executive summary and their ratings are:
★★★★★ report
You have in mind a companion for executive summary and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of executive summary in all years. Click on graph for more.
executive summary
abstract
introduction