In The Godwulf Manuscript, although Parker creates Spenser in the mold of Spade and other early hard-boiled characters, Spenser is also very much a...

Hard-boiled detective fiction grew from roots in pulp magazines. Writers working in this genre seek realism, but their works are often sensationalist, full of sex, violence, and, in some cases, raw language and/or slang. Detectives often find themselves tumbling into lurid situations, and drugs or drinking are very common.

All of these are definitely present in The Godwulf Manuscript. There's casual violence--Dennis, the college would-be thug who swings on Spenser for encroaching on his woman--and more serious violence, such as the death of the same character (Dennis).

Spenser only fully departs from the hard-boiled tradition later in the series, but you can identify points in this novel which signal Spenser's later characteristics. Some of these are visible early in the book: Spenser's wit ranges more widely and actively than most hard-boiled detectives.

Spenser's reading habits are also quite broad, and though these habits really evolve later in the story, one thing that sets him apart is his understanding of literature, art, and history.

Finally, Spenser is much more reflective than the hard-boiled detective, even doubting his own meaning at times.