Conversation so far:
Who was Helen Duncan?
the medium Helen Duncan.
How was Harry Price connected to Helen Duncan?
Price had proven through analysis of a sample of ectoplasm produced by Duncan, that it was made of cheesecloth.
Did he invesitgate other things related to Helen?
Duncan reacted violently at attempts to X-ray her, running from the laboratory and making a scene in the street.
What other involvement did he have with Helen?
Price wrote up the case in Leaves from a Psychist's Case Book (1933) in a chapter called "The Cheese-Cloth Worshippers".
Did Price write anything else?
Price later re-published the Society's experiment in a pamphlet of his own called Cold Light on Spiritualistic "Phenomena" - An Experiment with the Crewe Circle.

Question: Did he work closely with anyone else?
Self-contained rewrite: Did Harry Price work closely with anyone else aside from Helen Duncan?