Definitely a photo album. The quality of the photographs is poor to good, which is to be expected and is acceptable. Very little text, except for the picture captions.
-- 2/3+ of a page of introductory text
-- An excellent page (page 4) summarizing the versions!
-- A very good page (page 5) identifying the 6 (U1 - U6) Conversion sets and 7 (R1 - R7) Equipment sets
-- A page (page 45) of data on Luftwaffe operational units
-- A page (page 46) of technical data of the major versions
-- Good to very good line drawings (pages 11, 29, 41 and 45)

Some minor negatives:
-- I hate the use of Me 109
---- Page 31 has 'ME-109F' hand written on a photo of a captured Bf 109F-1 in U.S. markings (this is OK)
---- Page 2 (the back of the title page) has the original title "... Me 109 ..." (that's weird?)
-- Neither the version summarization (page 4) nor the technical data page (page 46) has the number built
---- The introductory text summarizes the number built by year, which is good
-- The Bf 109Z (twin version) is only briefly mentioned in the summarization data ( )