Philip is a lonely private detective, broken by the world, and barely hobbling along in daily life. Marlowe's cognitive leap at the end of the book to solve the mystery left the reader behind and felt more like divine intervention than that of a human detective. The mystery on a whole was short and only really addressed at the end of the book, this may be on account of the novel being comprised of two smaller short storied recycled and meshed together. I'd also like to point out that epileptics are not psychotic just because they are epileptic.
There were also many things well handled in the novel that balanced out the harsh aging effects. The characters were well described, vivid, and each in their own way human and easy to relate to. Marolowe's narrative voice was exquisite in how it was written, strengthening his impact on the story and adding a blunt but clear thought process to an otherwise unwieldy story. Just as with Marlowe, Carmen and Vivian were written well enough for you to challenge their motives and when the story comes to a close, their voices make the reveal acceptable.
Recommendation: Philip Marlowe's outdated language, deep rooted prejudices, and blatant hate for anything not in his sphere of control made it hard to read this story and accept Marlowe as character worthy of my time spent reading his adventure. Though a classic, and a well documented influence in modern movie, book, and video game history, I would recommend this book to be read as a historical reference and learning experience only. Take the good with the bad and for someone more interested in mysteries and the cops versus robbers genres, this might be one you'll love and read time and again.