Chetham's Library holds more than 100,000 volumes of printed books, of which 60,000 were published before 1851. They include especially rich collections of 16th- and 17th-century printed works, periodicals and journals, local history sources, broadsides and ephemera.
This library was the meeting place of Karl Marx and Engels when Marx visited Manchester. The economics books Marx was reading at the time can be seen on the shelf in the library, as can the window seat where they would meet.
The Manchester Free Grammar School for Lancashire Boys was built between the church and the college buildings between 1515 and 1518. The college was dissolved in 1547 by the Chantries Act and sold to the Earl of Derby. It was re-founded as a catholic foundation by Queen Mary and again disbanded by Protestant Queen Elizabeth I. In 1578 it was re-founded by charter as Christ's College and re-occupied by the warden and fellows. In the Civil War it was used as a prison and arsenal. In 1653 the college buildings were bought by the bequest of Humphrey Chetham, for use as a free library and blue coat charity school. Additions were made to the buildings by J. E. Gregan (1850s), Alfred Waterhouse (1878) (grade II listed), and J. Medland Taylor (1883–95). Manchester Grammar School was extended along Long Millgate in 1870. Manchester Grammar School moved to Fallowfield in the 1930s, and after standing empty for many years' the original building was destroyed during the Second World War, leaving only its new block. This became part of Chetham's School of Music in 1978. The old college building, which became the music school in 1969, still incorporates Chetham's Library and is grade I listed.