BIGFOOT: MAN OR BEAST is a very thorough, well-made documentary. Whether you believe these creatures actually exist or not, this is a fair treatment of the subject matter. It's not as absurd as one might expect either, since everyone involved comes across as sincere.
There are the eye witnesses and their retelling of their experiences, as well as experts both pro and con. Sightings as far back as the 1920's are discussed. There are also healthy doses of voiceover narration.
SPECIAL NOTE: This movie contains the famous 16mm video that has become the signature footage of the creature.
Of course, this did come out in the early 1970's, so it reflects its era. It's handled far more seriously than more recent Bigfoot exposes, which have usually been in the form of "reality shows".
This documentary is required viewing for the true enthusiast...