There were 6 MCDP handbooks -- I helped edit a re-release of #6 as a policy intern/college student after getting out of the USMC. See also: https://grc-usmcu.libguides.com/research-topics/main/usmc-do... (https://grc-usmcu.libguides.com/research-topics/main/usmc-doctrine) But I agree with parent's point -- MDCP #1 Warfighting is pretty good. If you're a military nerd all 6 are great, but if you're just going read one of them then definitely stick to Warfighting.
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