The introduction of the chapter discusses the frustration experienced by many investigators in establishing human tumor cell lines due to numerous unsuccessful attempts. However, the authors present a different perspective, highlighting that successful establishment of cell lines can be achieved using standard techniques and commonly known medium and serum combinations. They have established 31 new cell lines from 30 patients' tumors, both primary and metastatic, solid or effusive. The chapter emphasizes the importance of meticulous attention to detail in tissue culture and the need for a large collection of well-characterized, contamination-free human tumor cell lines to represent various tumor types. The methods of collecting tumor specimens, including solid tumors and metastases, are described, with a focus on ensuring sterility and avoiding contamination from surgical disinfectants.The introduction of the chapter discusses the frustration experienced by many investigators in establishing human tumor cell lines due to numerous unsuccessful attempts. However, the authors present a different perspective, highlighting that successful establishment of cell lines can be achieved using standard techniques and commonly known medium and serum combinations. They have established 31 new cell lines from 30 patients' tumors, both primary and metastatic, solid or effusive. The chapter emphasizes the importance of meticulous attention to detail in tissue culture and the need for a large collection of well-characterized, contamination-free human tumor cell lines to represent various tumor types. The methods of collecting tumor specimens, including solid tumors and metastases, are described, with a focus on ensuring sterility and avoiding contamination from surgical disinfectants.