https://www.britannica.com/biography/Samuel-Johnson/Maturity-and-recognition
The Britannica article has a lot of good information.
In 1746, a group of publishers approached Johnson with an idea about creating an authoritative dictionary of the English language.[67] A contract with William Strahan and associates, worth 1,500 guineas, was signed on the morning of 18 June 1746.[75] Johnson claimed that he could finish the project in three years. In comparison, the Académie Française had 40 scholars spending 40 years to complete their dictionary, which prompted Johnson to claim, "This is the proportion. Let me see; forty times forty is sixteen hundred. As three to sixteen hundred, so is the proportion of an Englishman to a Frenchman."[67] Although he did not succeed in completing the work in three years, he did manage to finish it in eight.[67] Some criticised the dictionary, including Thomas Babington Macaulay, who described Johnson as "a wretched etymologist,"[76] but according to Bate, the Dictionary "easily ranks as one of the greatest single achievements of scholarship, and probably the greatest ever performed by one individual who laboured under anything like the disadvantages in a comparable length of time."[4]
Boswell's Life of JohnsonJohnson's biographer, Boswell, was as interesting as his subject.