FIDE Albums are booklets published by the FIDE (the International
Chess Federation) and containing the "best" problems from a three years
period. Around 1000 problems every time.
The point is not only to collect the best problems, but also to award
titles. Official titles for composers, e.g. International Master for
Chess Composition, are awarded on the basis of problems selected for
the FIDE albums. Every selection is worth a given number of points and
every title requires a given total.
Of course, there are precise rules for submissions, selections, points
given to multiple authors, etc. but this is not the place to explain
them. The important thing is that
they include a few retros.