“Why do we divide our world into contraries? Why do we perceive and interpret so many of life’s contraries as mutually exclusive, either/or dichotomies such as individual vs. collective, body vs. mind, nature vs. nurture, cooperation vs. competition? J. A. Scott Kelso and David Engstrøm contend that ubiquitous contraries are complementary and propose a comprehensive, empirically based scientific theory of how the polarized world and the world in between can be reconciled. They nominate the squiggle sign (~), as symbolic punctuation for reconciled complementary pairs, reconciliations grounded in the science of coordination called Coordination Dynamics. The book provides a methodology for this evolving theory of brain~behavior applicable to any field and level, with potential to inspire successful reconciliations within~between disparate fields.