Cells are functional units of life that process inputs from their microenvironment – chemical and mechanicals interactions with their neighbors, soluble factors, and with their extracellular matrix – and map these to phenotypic outputs. Efforts to program the behavior of cells has relied in large part to niche engineering approaches, where the microenvironment of the cell is manipulated to control changes in cell proliferation, death, motility, identity, etc. Recent advances with genetic engineering have now opened the door to programming the inner regulatory network of the cell, allowing us to move cells across the Waddington landscape in directs previously thought to be impossible, such as with the conversion of somatic cells to a stem cells state. With growing approaches to cell fate programming, in this collection we explore techniques for both reverse and forward engineering cellular behavior, both at the single cell and population level.