The 39 Categories of Melakhot Prohibited on Shabbat
“The Talmud enumerates 39 general categories of labors that went into the construction of the Tabernacle. These are the archetypal labors that must be refrained from on the Sabbath.
All manifestations of these 39 general labors make up the parameters for what is acceptable and unacceptable for the Sabbath today…
Based on these archetypes it also becomes possible to assess if a new invention or technology is Sabbath appropriate.”