From the 1967 LP "H.P. Lovecraft"

8^9: Bend the 8th fret a half tone up to sound like the 9th fret
h: Hammer-on
p: Pull-off
: slide down neck

Bass line arranged for guitar:

|------------------------------------|
|------------------------------------|
|--------7----5---------------------7|
|------------------7--5-------6--7---|
|5-------------------------5---------|
|------------------------------------|

Bass plays this riff once before drums comes in and once more before guitar comes in.

The first guitar that is heard is just a D chord. Riff below is played 2x, but without slide

Guitar riff in verse (only played on every other repeat of above bassline):
|------------------------------------|
|------------------------------------|
|----7-----7------7------7-------|
|----7-----7------7------7-------|
|----5-----5------5------5-------|
|------------------------------------|


Guitar in chorus:

       D (second guitar)
|-------------------h--p----10---|
|--9^10-9^10-9^10--9-10-9--------|
|-------------------------7------|
|--------------------------------|
|--------------------------------|
|--------------------------------|

A guitar with either no or light distortion also plays the verse riff in the chorus. It's 
difficult to say if it's played below the riff above, but when the riff above is not played,
it's played; Every time in the first chorus, but only every other time in the other choruses

Verse

Chorus

Bridge (or organ solo or whatever you might call it):
|-------------------------------------------|
|-------------------------------------------|
|7.----7---7.----7---7.----7---7.----7--|
|7.----7---7.----7---7.----7---7.----7--|
|5.----5---5.----5---5.----5---5.----5--|
|-------------------------------------------|


Guitar riff after "bridge":
|--------------------------------------------------
|--10-10-10-12-12-12-12-12-12-12-13-13--13-13-----*
|--------------------------------------------------
|--------------------------------------------------
|--------------------------------------------------
|--------------------------------------------------

 -----------------------------------h-----h-----h-----h-----h-----h----------------|
 15-15-15-13-13-13-12-12-12-12-12-12-13-12-13-12-13-12-13-12-13-12-13-12--10-10-10-|
 ----------------------------------------------------------------------------------|
 ----------------------------------------------------------------------------------|
 ----------------------------------------------------------------------------------|
 ----------------------------------------------------------------------------------|


Verse

Chorus

Bridge

Riff after bridge twice. Until the *, the bridge riff is played by the second guitar. After
that, the D chords played in the chorus are played for the rest of the song.

Strum a D chord in an arpeggio like rhythm (open D chord is most likely used, instead of the
ones played on the 5th fret in the verse and bridge) on the first beat of each bar 4 times

End on a D chord (the last time of the 4 times mentioned above).