1. Introduction  
2. Sample selection and stellar luminosities with Hipparcos and/or Gaia parallaxes  
2.1. Initial sample selection  
2.2. Determination of stellar luminosities and final sample based on Gaia DR2  
3. Observations and spectra processing  
3.1. Observations and data reduction  
3.2. Determination of effective temperature and gravity  
3.3. Determination of $I F e/H J$ and of lithium abundances  
3.4. Comparisons with other studies  
4. Comparison with stellar model predictions  
4.1. Mass range and evolution status of the sample stars  
4.2. Li behaviour - The impact of rotation-induced mixing and thermohaline mixing  
4.3. Li-rich stars  
5. Conclusions