A popular way to collect postal history is to build the collection around a set of stamps the collector particularly likes. The ideal set will have been used for a number of years, have significant variety in the stamps themselves (lots of colors is good!) and cover a period of years during which there was interesting mail contact with other countries, rate changes and maybe even the introduction of airmail!
There is a little known set from South America that matches all these
requirements. It is known among collectors as the "Presidentes of Chile".
The first set, issued in 1911, was produced by the American Banknote
Company. A set of 15 stamps in its basic form, it is a superb example
of the engraving and stamp production talents of that company at the
time. You will find it in Scott as #98-112, and Stanley Gibbons as
#135-49. (The pictures in Scott do not do this set justice!) Another
seven values (color changes plus additional values) were supplied by
ABNC during 1912-13. In 1915, production was taken over by the Chilean
Three values from the original set by the American Banknote Co.
Local production resulted in a change to typography and lithography
from engraving and resulted in a number of interesting combinations
of frames and centers using one of each of the printing methods. Over
the following 15 years, the stamps were redrawn, watermarked paper was
introduced and many varieties that did not find their way into a
listing in the standard catalogs appeared.
As an added bonus, the set was chosen for overprinting for use as the
first airmail stamps (ignoring the first 1927 set in the catalogs which
was for use on a local Santiago-Valparaiso flight). As a result, all
the interesting covers of the formative airmail years of 1928-32 bear
the Presidente airmails. In my opinion, these covers are some of the
most attractively franked airmail covers in the world, nearly always
carrying multiple copies of different stamps in many colors.
Three of many values overprinted for airmail use.
A representative selection of covers
All considered, this set of stamps represents an astonishingly fruitful field of study in a philatelic area that is not overly crowded and has many different facets to explore. Chile specialist groups exist -small, but amazingly helpful and experienced. There is also a good depth of existing study and articles upon which to draw. If you are interested, contact me at firstname.lastname@example.org and I will put you in touch by email.