Although the first crystallographically characterized lanthanide dinitrogen complex was reported in 1988 with samarium, it is only in recent years that this field has expanded to include fully characterized examples for the entire series of lanthanides. The development of lanthanide dinitrogen chemistry has been aided by a series of unexpected results that present some good lessons in the development of science. This review presents a chronological account of the lanthanide dinitrogen chemistry discovered in our laboratory through the summer of 2004.Key words: lanthanides, dinitrogen, reduction, alkali metal, nitrogen fixation, diazenido.