Sounds like it may have been "bushwalks in the sydney region" by national parks association which are pretty good for intro walks and the popular longer trips.
a nice list of books is on the confed page here:
http://www.bushwalking.org.au/nlib.htmlotherwise there's
http://www.wildwalks.com/ where you can print out walk details
and also
http://ozultimate.com/bushwalking/ which has detailed trip reports/occasional nice sketch maps (and also a book list)
if you're walking on trails (and if you're not, too) generally you'd want to take a 1:25k scale topographic map of the area with you as well, to use in combination with the sketch maps from books/the web
enjoy
by the way to answer your question yes I'd recommend the 'bushwalks in the sydney region' books. walks in and within ~120 km of sydney with grading, time, transport options, etc. I think some of the books may be hard to come across these days. maybe give the shops on kent st a buzz to see if they still sell bushwalking books ? glenbrook visitor's had the NPA books when I last dropped in so hopefully they still have a collection for sale