Dear experimenter, since the first edition in 2004, the 4th edition of the Immuno-Experimenter has now been published. This work presents the methodological diversity of immunology by explaining common methods in a simple way and addressing their advantages, disadvantages, and critical points. Following an introduction to antibodies, their function and source in vivo, as well as their application as an immunological tool, methods such as flow cytometry, immunoblotting, ELISA, and similar immunoassays are covered, along with cell separation techniques and in-situ immunolocalization. As an additional bonus, readers are given the opportunity to gain insights into the depths of biostatistics. The Immunology Experimenter is aimed at technical assistants, laboratory technicians, graduates, and doctoral students, as well as anyone interested in immunology. Informative.