High energy colliding beams; What is their future? / B. Richter -- Proton-proton and proton-antiproton colliders / W. Scandale -- Electron-positron circular colliders / K. Oide -- Ion colliders / W. Fischer and J.M. Jowett -- Electron-proton and electron-Ion colliders / I. Ben-Zvi and V. Ptitsyn -- Linear colliders / A. Yamamoto and K. Yokoya -- Muon colliders / R.B. Palmer -- The photon collider / J. Gronberg -- Collider beam physics / F. Zimmermann -- Collision technologies for circular colliders / E. Levichev -- Andy Sessler: The full life of an accelerator physicist / K.-J. Kim, R.J. Budnitz and H. Winick