PI3K - From the Bench to the Clinic and Back -- PI3K Book Introduction -- PDK1: The major transducer of PI 3-Kinase actions -- Protein Kinase B (PKB/Akt), a key mediator of the PI3K signaling pathway -- Regulatory subunits of class IA PI3K -- The Regulation of Class IA PI 3-kinases by Inter-Subunit Interactions -- Phosphoinositide signalling pathways in metabolic regulation -- Role of RAS in the regulation of PI 3-kinase -- More than just kinases: The scaffolding function of PI3K -- PI3K signalling in neutrophils -- PI 3-kinase p110beta regulation of platelet integrin alphaIIbbeta3 -- PI3Ks in lymphocyte signalling and development -- PI3 kinase regulation of skeletal muscle hypertrophy and atrophy -- Taking PI3Kdelta and PI3Kgamma one step ahead - Dual active PI3Kdelta/gamma inhibitors for the treatment of immune-mediated inflammatory diseases -- Oncogenic Mutations of PIK3CA in Human Cancers -- Structural Effects of Oncogenic PI3Kalpha Mutations -- Comparing the roles of the p110alpha and p110beta isoforms of PI3K in signaling and cancer -- Phosphatidylinositol 3-kinase (PI3K): The oncoprotein -- AKT Signaling in Physiology and Disease -- Faithfull modeling of PTEN loss driven diseases in the mouse -- PI3K as a target for therapy in haematological malignancies -- Clinical development of Phosphatidylinositol-3 kinase pathway inhibitors -- New inhibitors of the PI3K-Akt-mTOR pathway: Insights into mTOR signaling from a new generation of Tor kinase domain inhibitors (TORKinibs) -- Small molecule inhibitors of the PI3-kinase family -- Targeting the RTK-PI3K-mTOR axis in malignant glioma: overcoming resistance -- Subject index. From humble beginnings over 25 years ago as a lipid kinase activity associated with certain oncoproteins, PI3K (phosphoinositide 3-kinase) has been catapulted to the forefront of drug development in cancer, immunity and thrombosis, with the first clinical trials of PI3K pathway inhibitors now in progress. Here the authors give a brief overview of some key discoveries in the PI3K area and their impact, and include thoughts on the current state of the field, and where it could go from here.