I also keep a revision history log in the front of the document. The revision history notes the sections and major changes and the date they were done. Sometimes the reason they were done. Here's a sample below.
Version 1.6 08/28/2008 Changes for consistency with PPM
Version 1.7 12/10/2008 Modify section 5.5 adding Production Database Changes
Version 2.0 2/9/2009 Modify for changes in procedures required by Dimensions (Starbase replacement) in Section 5.
Version 2.01 2/10/2009 Clarifications in verbiage for Section 5
Version 2.10 3/11/2009 Clarify section 5.2, add and change reviewers and approvers, add disclaimer for PLCS UAT Process
Version 3.0 7/23/2010 Changes in section 5.4 to reflect changes in Testing process. Changes to reflect ITSM rather than HEAT in section 5.5, changed CCR to RFC in many places, changed reviewers and approvers in Appendix D
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The trouble with doing something right the first time is that nobody appreciates how difficult it was - Steven Wright