Using the achievements of my research group over the last 30+ years, I provide evidence to support the following hypothesis: By complementing each other, cooperating reasoning process can achieve much more than they could if they only acted individually. Most of the work of my group has been on processes for mathematical reasoning and its applications, e.g. to formal methods. The reasoning processes we have studied include: Proof Search: by meta-level inference, proof , abstraction, analogy, symmetry, and reasoning with diagrams. Representation Discovery, Formation and Evolution: by analysing, diagnosing and repairing failed proof and planning attempts, forming and repairing new concepts and conjectures, and forming logical representations of informally stated problems. ∗ I would like to thank the many colleagues with whom I have worked over the last 30+ years on the research reported in this paper: MECHO/PRESS (Lawrence Byrd, George Luger, Chris Mellish, Rob Milne, Richard O’Keef...