This online edition of Crockford's Clerical Directory contains information dating back to 1968. If you are looking for information that predates this, there are other sources of information that may be useful:
1540 to 1835
The Clergy of the Church of England Database (CCEd) is a collaborative project offering online biographical data on clergymen for the period 1540-1835 from archives in England and Wales.
CCeD also contains information on dioceses (including lists of bishops), and on locations where clergy served. The terminal date of the project (1835) marks the period at which biographical data about clergymen becomes more accessible due to such publications as the Clergy List (and later, Crockford's Clerical Directory).
1835 to 1967
Lambeth Palace Library is the historic library of the Archbishops of Canterbury and the principal library and record office for the history of the Church of England. Its rich collections are important for an immense variety of topics, as well as a significant resource for genealogy.
The library holds a sequence of historic copies of Crockford's Clerical Directory and will check them to answer specific enquiries. They may also be contacted about any period due to the diverse range of printed sources they hold.