Three general types of WPB regulations are presented: (1) Those which deal with priorities and preference ratings (P‐43, P‐100, P‐90, and forms PD‐1A and PD‐25A); (2) Limitation Order L‐144; and (3) Priorities Regulation No. 10. P‐43 assigns a blanket preference rating of A‐2 to purchases by certain research laboratories; P‐100 assigns an A‐10 rating to the purchase of supplies by certain ``producers'' including educational institutions; P‐90 sets up the Production Requirements Plan under which certain producers must and others may operate, obtaining priorities assistance through the use of Form PD‐25A; Form PD‐1A may be used to apply for priorities assistance in securing required material and equipment not covered in other plans. Limitation Order L‐144 limits the purchase of laboratory equipment containing critical materials to certain specified users and to users specifically approved by the WPB Supplementary rulings and unofficial interpretations have been obtained concerning L‐144. Priorities Regulation No. 10 sets up an allocation classification system whereby certain symbols must be added to orders indicating the end use of the material being purchased.