The cytology and connections of the lateral habenula (LHb) are reviewed. The habenula is first introduced, after which the cytology of the LHb is discussed mainly with reference to cell types, general topography and descriptions of subnuclei. An overview of LHb afferent connections is given followed by some details about the projections to LHb from a number of structures. An overview of lateral habenula efferent connections is given followed by some details about the projections from LHb to a number of structures. In considering the afferent and efferent connections of the LHb some attention is given to the relative validity of regarding it as a bi-partite structure featuring ‘limbic’ and ‘pallidal’ parts. The paper ends with some concluding remarks about the relative place of the LHb in adaptive behaving.