The Blue Book provides a list of the representatives of Member States to the United Nations. The complete collection from 1946 up to today is now conveniently accessible and searchable in the UN Digital Library.

Direct link to the Blue Book in the UN Digital Library: https://digitallibrary.un.org/search?ln=en&as=1&m1=p&p1=Permanent+Missions+to+the+United+Nations&f1=series&op1=a&m2=a&p2=&f2=&op2=a&m3=a&p3=&f3=&dt=&d1d=&d1m=&d1y=&d2d=&d2m=&d2y=&rm=&ln=en&sf=year&so=d&rg&_gl=1*k1yp5i*_ga*MTgxODEwODUwNS4xNzE1ODAwOTE1*_ga_TK9BQL5X7Z*MTcxODk4MzQ3NS4yLjEuMTcxODk4MzUwOC4wLjAuMA..