The article provides a comprehensive overview of the ABC model of flower development, tracing its historical development and current understanding. The model, formulated by a few pioneering plant developmental geneticists, has been instrumental in advancing the field of floral biology. The authors highlight the model's ability to explain various floral mysteries, including the regulatory processes that generate spatio-temporal expression patterns of floral homeotic genes, the mechanisms by which ABC genes specify distinct organ identities, and the evolutionary processes that generate morphological diversity. The history of the ABC model is traced from its early formulations to its current form, with specific milestones noted. The authors discuss the historical context of flower variants described in ancient texts, such as those by Theophrastus and Pliny, and the recognition of homeotic transformations in flowers. They also delve into the genetic and molecular foundations of the model, detailing the discovery and characterization of key genes like *APETALA1* (*AP1*), *APETALA2* (*AP2*), *PISTILLATA* (*PI*), and *AGAMOUS* (*AG*). The article explains how the ABC model postulates that three distinct gene activities (A, B, and C) act alone and in combination to specify the four types of floral organs. It highlights the mutual antagonism between A and C activities and the role of B-class genes in promoting either petals or stamens. The authors also discuss the discovery of E-class MADS box genes, which are necessary for the specification of floral organ identity and can convert leaves into floral organs. The molecular and genetic extensions of the ABC model are explored, including the identification of paralogs and their roles in different species. The article addresses the conservation and subfunctionalization of A- and B/C-class genes across angiosperms, and the evolutionary implications of gene duplications and regulatory changes. Finally, the authors discuss the regulatory networks that control the spatio-temporal expression of ABC genes, emphasizing the multi-layered processes involving hormonal signaling, transcription factors, and chromatin remodeling. They highlight recent breakthroughs in understanding the molecular mechanisms behind floral organ specification and the challenges that remain in fully elucidating the ABC model.The article provides a comprehensive overview of the ABC model of flower development, tracing its historical development and current understanding. The model, formulated by a few pioneering plant developmental geneticists, has been instrumental in advancing the field of floral biology. The authors highlight the model's ability to explain various floral mysteries, including the regulatory processes that generate spatio-temporal expression patterns of floral homeotic genes, the mechanisms by which ABC genes specify distinct organ identities, and the evolutionary processes that generate morphological diversity. The history of the ABC model is traced from its early formulations to its current form, with specific milestones noted. The authors discuss the historical context of flower variants described in ancient texts, such as those by Theophrastus and Pliny, and the recognition of homeotic transformations in flowers. They also delve into the genetic and molecular foundations of the model, detailing the discovery and characterization of key genes like *APETALA1* (*AP1*), *APETALA2* (*AP2*), *PISTILLATA* (*PI*), and *AGAMOUS* (*AG*). The article explains how the ABC model postulates that three distinct gene activities (A, B, and C) act alone and in combination to specify the four types of floral organs. It highlights the mutual antagonism between A and C activities and the role of B-class genes in promoting either petals or stamens. The authors also discuss the discovery of E-class MADS box genes, which are necessary for the specification of floral organ identity and can convert leaves into floral organs. The molecular and genetic extensions of the ABC model are explored, including the identification of paralogs and their roles in different species. The article addresses the conservation and subfunctionalization of A- and B/C-class genes across angiosperms, and the evolutionary implications of gene duplications and regulatory changes. Finally, the authors discuss the regulatory networks that control the spatio-temporal expression of ABC genes, emphasizing the multi-layered processes involving hormonal signaling, transcription factors, and chromatin remodeling. They highlight recent breakthroughs in understanding the molecular mechanisms behind floral organ specification and the challenges that remain in fully elucidating the ABC model.