ART stimulation in the next decade - an overview -- Natural cycle IVF - an overview.-Natural Cycle IVF: Follicle Physiology and Treatment Costs.-The Use of Clomiphene Citrate in Natural Cycle IVF -- The Role of Non-Steroidal Anti-Inflammatory Drugs in Natural Cycle IVF -- Theoretical Backgrounds of the Natural Cycle and Other Minimal Stimulation Cycles: From Follicle Observation to Embryo Transfer -- Ovarian Stimulation in Patients with Ovarian Insufficiency -- Mono-Follicular Stimulation in PCOS Patients -- Luteal Phase Support in Natural Cycle and Minimal Stimulation IVF -- Budget IVF Using Clomiphene, hMG, and Antagonists -- Vitrification Is the Keystone to Minimal Stimulation IVF -- Lessons Learned and Future Challenges.