Greening the analytical process is a current demand in many application fields, especially those involving the treatment of relatively large amounts of samples through preparation protocols encompassing several independent treatment steps. The determination of minor compounds in complex matrices, such as foodstuffs and environmental samples, is representative of this type of analysis. In these research areas, the very low levels at which specific compounds need to be accurately determined, combined with the complexity of the matrix in which they are entrapped, frequently makes it essential to use laborious multistep sample-preparation procedures. As a consequence, conventional treatment procedures in these types of analysis use relatively large amounts of reagents and solvents, have long analysis times and generate relatively large amounts of wastes per sample analyzed. In most cases, integration of the different treatment steps is very limited, resulting in continual exposure of the analyst to chemicals and making procedures prone to analyte loss and/or degradation due to the continuous sample manipulation. In this context, any modification that contributes to solving (or at least minimizing) any of these shortcomings of conventional sample-treatment methodologies or to greening them should be considered advantageous. The many efforts in the past two or three decades in sample preparation have yielded a number of well-accepted, established extraction and preconcentration techniques that are able to fulfill (at least partially) some of these requirements for the miniaturized treatment of liquid and viscous samples. Representative examples, such as single-drop microextraction (SDME), solidphase microextraction (SPME) and its in-tube version, or stir-bar sorptive extraction (SBSE), are highlighted in review papers in this Special Issue. The latest additions in hollow-fiber microextraction (HFME) [1] and related modern solvent-based microextraction techniques [2], dispersive liquid-liquid microextraction (DLLME) [3], or miniaturized solid-phase extraction (SPE) [4,5] and other SPEbased techniques [6], can be found in recent literature. However, developments in the treatment of semi-solid and solid samples have been much more limited [7].