War­ren Buffett’s let­ters to the share­hold­ers of Berk­shire Hath­away are read and quoted widely, com­ing to be regarded as one of the most impor­tant annual pub­li­ca­tions in the busi­ness and invest­ing world.

Over the years the let­ters have cov­ered, in quite some detail, almost every impor­tant aspect of invest­ing. The (incred­i­bly lack­lus­tre) Berk­shire Hath­away web­site pro­vides an archive of these let­ters (back to the 1970s, at least) and many other doc­u­ments also worth a browse.