The months of lockdown have been very productive, particularly in writing material that I did not have time to write before. In particular, I was invited to write a follow up review for Expert Opinion on Drug Discovery (EODD) in the field of Ligand Efficiency Indices (LEIs). This would be a follow-up article to the one I published in 2007, when the area of LEIs was just starting to take off. Recently, I just published this invited review with the title Ligand Efficiency Indices for Effective Drug Discovery: a unifying vector formulation. The ideas presented have been developing since 2007 and growing from the early definitions of SEI, BEI, to a unifying vector formulation where SEI, BEI are the x and y components (respectively), of a Ligand Efficiency vector named vLEI (bold denotes vector). Details can be found in the recently published paper that can be found in the ‘AtlasCBS’ and ‘Efficiency based drug design’ tabs. A direct link to the publication can be found here also. https://www.tandfonline.com/eprint/PBDJ8MUPXMY4TYCKC22T/full?target=10.1080/17460441.2021.1884065