For those romanly numerate, Journals were grouped by annual volume from I (1955) to XXVI (1980); from 1965 there were 4 issues a year (Jan, Apr, July, Oct, except 1973 which was March, July, Sept, Dec) but from 1974 there were 3 issues a year (March, July, Nov), excepting 1979 which had an additional Sept issue. Since 1981 volumes have been grouped in 3-year sets, Vol XXVII being 1981-83, XXVIII 1984-86, XXIX 1987-89, XXX 1990-92, 31 (roman abandonment) 1993-95, 32 1996-98, 33 1999-2001, 34 2002-2004, 35 2005-2007, 36 2008-2010, 37 2011-2013. There continued to be 3 issues a year (March, July, Nov) excepting 1993 and 2004 which both had additional May issues, and 2007 which had an additional December issue (the 200th Journal).
There is no comprehensive index to the Journal. Three combined indexes were published covering volumes I to X, XI to XX and XXI to XXVI. After this, a separate index was published in the last Journal of each volume excepting volumes 35 and 36 which were issued as separate booklets.
However, the separate index files have now been OCR read and combined into one pdf so it is word searchable. Please note that different indexes were prepared to different formats, so they lack a common set of rules. (please note that the title page to the volume 32 index incorrectly refers to volume 31)
The combined document covering volumes 1-36 is available here.