An exact analytical method is described to solve the diffraction and radiation problems of a group of truncated vertical cylinders. In order to account for the interaction between the cylinders, Kagemoto and Yue's exact algebraic method is utilized. The isolated cylinder diffraction and radiation potentials are obtained using Garret's solution, and evanescent mode solutions are derived in a similar manner. Numerical results are presented for arrays of two and four cylinders. Comparisons between the results obtained from the method presented here and those obtained from numerical methods show excellent agreement.