Recommended Books

I have lots of my own teaching material but you may wish to accompany your lessons with some of these:
Classical Guitar
The Guitarist's Way by Petter Nuttall & John Whitworth
are aimed at young beginners
Very Easy Guitar Tunes are good for those reading music

'Julio s. Sagreras Guitar Lesson Books 1-3 (Mel Bay)
show excellent techniques for dedicated students.

Acoustic & Electric Guitar
Any books by MI (Musicians Institute published by Hal Leonard)
are very good books although many are for advanced students.
'Guitar Basics' and 'Rhythm Guitar' are good for novices.

Electric Guitar

The 'Rock School' syllabus is worth following
and gives you the option of working towards grades.
Grade books
For electric guitar we recommend the Rock School syllabus.
The exams (1 to 8) are fully accredited by the QCA (Qualifications and Curriculum Authority).

For classical guitar the most established syllabus is:
ABRSM (The Associated Board of the Royal Schools of Music)

The Registry of Guitar Tutors (RGT) offer grades in Electric, Acoustic and Classical styles
RGT (Registry of guitar tutors)