What is the hotel-related organization abbreviated as HMMBA and
active in the U.S. during the late 1800's and early 1900's?

Greetings, buckram!

H.M.M.B.A. stands for:
"Hotel Men's Mutual Benefit Association"

From the US Library of Congress' Online Catalog:
"LC Control Number:
     07008609
Type of Material:
     Book (Print, Microform, Electronic, etc.)
Personal Name: 
     James, G[eorge] Wharton, 1858-1923. [from old catalog]
Main Title:
     The H.M.M.B.A. in California, by G. Wharton James ...
     Published/Created: Pasadena, Cal., G.W. James, 1896.
     Description: 338 p. incl. front., illus., ports., facsim. 26 cm.
Notes:
     An account of the annual meeting of the
     Hotel men's mutual benefit association in 1896. 
Subjects:
     Hotel men's mutual benefit association. [from old catalog]
     California--Description and travel--1869-1950. 
         [from old catalog]"
http://catalog.loc.gov/cgi-bin/Pwebrecon.cgi?v3=2&ti=1,2&SEQ=20021122145223&Search_Arg=%22H.M.M.B.A.%22&Search_Code=FT*&PID=29385&CNT=25&SID=10


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