Franz Brentano (1838-1917) is almost unique as a forefather of both Analytic and Continental philosophy. His claim to fame is the reintroduction of intentionality (the 'aboutness' of consciousness) to the modern philosophy of mind. In the Analytic tradition this is treated as (or as closely akin to) representation. In the Continental tradition intentionality is the leitmotiv of phenomenology. Brentano attracted a variety of students during his lifetime, a group of influential philosophers, psychologists, and others. Ryan Hickerson's book offers new interpretations of a central philosophical concept employed in the Brentano School. He argues against the now-standard misreading of Brentano (in both the Analytic and Continental traditions) as Immanentist, i.e. someone who believed that mental contents exist solely within the mind. Hickerson does this by tracing Brentano's notion of a 'phenomenon' back to its origins in the French positivism of August Comte. He then displays Brentano's students as attempting to correct the 'problems' each found in Brentano's treatment of mental content, including: (1) Twardowski's division of subjective contents from worldly objects, his part in a sea change in representational theories at the dawn of the 20th Century; (2) Meinong's ontology of non-existent objects, the reaction to Brentano made infamous by Russell; and (3) Husserl's 'breakthrough to phenomenology,' his advancement of mental contents as ideal. The History of Intentionality is a continuing history; this book will be very valuable for present-day specialists and students in phenomenology and the philosophy of mind.