Just read this (from Ralph Cunnington's EQ article 'A re-examination of the intermediate state of unbelievers') and thought it was worth sharing:
The history of the interpretation of the parables has been dominated by two contrasting approaches. Until the end of the nineteenth century, most interpreters adopted an allegorical approach, but this was convincingly challenged by modern cholarship which insisted that allegory is completely absent from the parables.<3> Unfortunately, this approach is itself flawed in that it verlooks the undeniable allegorical elements that are present in many of Jesus’ parables, and denies the authenticity of Jesus’ own allegorical interpretations of his parables (Matt. 13:18-23, 36-43).<4> As Klyne Snodgrass has noted, these scholars have ‘thrown out allegory, a literary form, while the problem was allegorizing, the interpretative procedure of reading into the parables a theology that Jesus did not intend’.<5> A preferable approach is to recognise the presence of allegory while being cautious not to read meaning into the parables which would not have been apparent to the original hearers.<6>
3. The forerunner and leader of this new approach was Adolf Jülicher, Die Gleichnisreden Jesu (2 vols.; Freiburg: Mohr-Siebeck, 1889). Jülicher denied that Jesus ever used allegory and claimed that all of Jesus’ authentic parables were in reality expanded similes. See the discussions in: Klyne Snodgrass, ‘From Allegorizing to Allegorizing: A History of the Interpretation of the Parables of Jesus’, in The Challenge of Jesus’ Parables (ed. Richard N. Longenecker; Grand Rapids: Eerdmans, 2000), 3-10; Robert H. Stein, ‘The Genre of Parables’, in Longenecker, Challenge, 30-34.4. Jeremias, The Parables of Jesus (London: SCM, 1972), 77-79.5. Klyne Snodgrass, Stories with Intent: A Comprehensive Guide to the Parables of Jesus (Grand Rapids: William B Eerdmans Publishing Co, 2008), 6.6. Craig L. Blomberg, Interpreting the Parables (Leicester: Apollos, 1990), 68-69.
I've read Blombeg's Interpreting the Parables and recommend it.