Preoperative localisation of non-palpable breast and axillary lesions is a cornerstone of contemporary breast-conserving surgery. As breast cancer screening becomes more widespread and imaging techniques more advanced, the detection of small, non-palpable lesions has increased significantly. This shift necessitates precise localisation methods to guide surgical excision and ensure complete removal of the target lesion with negative margins, while preserving surrounding healthy tissue. Accurate localisation is also critical in achieving optimal cosmetic results and reducing the need for re-excision procedures. Wire-guided localisation (WGL) has been the most widely used and time-tested technique for several decades. It involves the placement of a hook wire under imaging guidance to mark the lesion, enabling the surgeon to identify and excise it during surgery. This chapter provides a comprehensive review of WGL, including its indications, contraindications, equipment and wire types, step-by-step procedural technique under various imaging modalities, and key intraoperative considerations. This chapter also discusses advantages, common pitfalls, and logistical challenges associated with wire localisation. Despite its widespread use, WGL has limitations, such as wire migration, patient discomfort, and dependence on tightly coordinated surgical scheduling. These have driven the development of alternative wire-free localisation methods, which offer increased flexibility and improved patient experience. Among these, technologies like radiofrequency identification (RFID), radar reflectors, and magnetic seed localisation are gaining attention in clinical practice. These emerging techniques, along with potential future innovations including biodegradable markers and artificial intelligence-assisted localisation, are explored in detail in subsequent chapters.