ACAL -- An efficient adaptive chain oriented algorithm for the analysis of multiple chain closed queueing networks. This paper presents an Adaptive Chain Oriented Algorithm (ACAL) for the analysis of closed product form queueing networks with multiple chains. The algorithm calculates the joint queue length distributions as well as the mean performance values. It is shown to be more efficient than existing ones, e.g. MVAC, RECAL or DAC, in dealing with networks with a large number of chains and a small number of nodes. In addition, it has an adaptive nature, which further improves the efficiency of ACAL. The adaptive nature also distinguishes ACAL from existing algorithms.