Every Marine officer has his/her place within the officer corps, this is considered their 'linear number'--who is senior to whom. The "blue book" or "lineal list" (and also called the Navy Register) is an annual book that contains all the active duty officers of the Marine Corps within their respective ranks in order of precedence. The lineal lists can be an extremely useful historical tool as they can, depending on the year and/or version, contain information on the officer's location of service, lineal position, service number, and other beneficial information.
In a continuing effort to make more historical resources available online, the Marine Corps History Division has digitized the lineal lists from 1800 through 1933 and are making them available herein. Please Note: the books are very fragile and the scanning is the best that could be done given the condition of the original material. Also, we do not have a complete set so some years will not be available.