Modeling the Clustering of Objects

I review the main steps made so far towards the construction of a (semi) analytical model for describing the growth history of bound virialized objects or haloes in the gravitational instability scenario. I mainly focus on those models relying on the spherical collapse approximation which have led to the most complete description. I insist on the different assumptions of each model and outline their main advantages and shortcomings. The work is divided in two parts: a first one dealing with the theoretical mass function of objects, and a second one dealing with the typical growth times and rates. Particular attention is paid to a new model making the practical distinction between accretion and merger events.