As 'Liar, Liar' gives resolution to the first two books in the 'Harriet Blue' series, you should probably read them first.
I find 'Liar, Liar' to be yet another book that could have been good, but isn't. The psychological warfare could have been interesting but it isn't: it's only banal and repetitive. The sub-characters are overworked stereotypes and the resolution to finding the bad guy is pretty unrealistic.
I can't imagine where Detective Harriet Blue goes from here (other than where the ending seems to actually be sending her). I can see no way to resurrect and/or redeem her character that would put her back where she was before beginning this escapade and without that why would we read a DETECTIVE Harriet Blue novel?
2 stars, very low C- with a recommendation that you consider the value of your time before picking up 'Liar, Liar' and that Patterson considers his reputation before releasing yet another unworthy novel. He is trading on his far too famous name for really awful books lately.