| Investigated, with ''into'' | 43 |
| Investigated, with "into" | 35 |
| Investigates, with "into" | 35 |
| Investigation into a social networking site? | 44 |
| Investigation into the death of a famous writer? | 48 |
| Investigation of one person after another? | 42 |
| Investigative division (and puzzle theme hint) | 46 |
| Investigative journalism piece, perhaps | 39 |
| Investigative journalist's piece | 36 |
| Investigative journalist's report | 37 |
| Investigative reporter's asset | 34 |
| Investigative reporter's specialty | 38 |
| Investigator in the USS Cole attack | 35 |
| Investigator of family problems, say | 36 |
| Investigator of many accidents, for short | 41 |
| Investigator of unnatural deaths | 32 |
| Investigator's employer: Abbr. | 34 |
| Investigators sometimes follow them | 35 |
| Investing formula used by a portfolio manager | 45 |
| Investing largely in money markets, say | 39 |
| Investing opportunity, for short | 32 |
| Investment activity, so to speak | 32 |
| Investment adviser's determination | 38 |
| Investment adviser's suggestion, for short | 46 |
| Investment broker's offering | 32 |
| Investment by a baseball player? | 32 |
| Investment company for a nudist camp? | 37 |
| Investment firm with an asterisk in its name | 44 |
| Investment firm's bathroom fixture? | 39 |
| Investment options for Batman's publisher? | 46 |
| Investment with a 2- to 10-yr. maturity | 39 |
| Investments for old age, for short | 34 |
| Investments for one's golden years, maybe | 45 |
| Investments usually held for yrs. and yrs. | 42 |
| Investor's concern, familiarly | 34 |
| Investor's online destination | 33 |
| Investor's option, for short | 32 |
| Investor's payment mechanism | 32 |
| Investor's purchase, perhaps | 32 |
| Invests with land, in olden times | 33 |
| Invigorates (with ''up'') | 41 |
| Invigorates (with "up") | 33 |
| Invigorates, with ''up'' | 40 |
| Invigorates, with "up" | 32 |
| Invigorating, with "up" | 33 |
| Invisible barrier in a sci-fi movie | 35 |
| Invisible-clothes wearer in an Andersen tale | 44 |
| Invitation abbr. concerning drinks | 34 |
| Invitation acknowledgment (abbr.) | 33 |
| Invitation for a Gateway Arch date | 34 |
| Invitation information specification | 36 |
| Invitation into a writer's home? | 36 |
| Invitation on a rep's button | 32 |
| Invitation only given in February | 33 |
| Invitation to cocktails with pianist Ramsey? | 44 |
| Invitation to one standing awkwardly near the bar | 49 |
| Invitation to the stage since 1972 | 34 |
| Invitation to wear someone's salad dressing? | 48 |
| Invitation's request, for short | 35 |
| Invite to an impromptu private meeting | 38 |
| Invite to one's apartment, say | 34 |
| Invite to one's penthouse suite | 35 |
| Invite to one's penthouse, e.g. | 35 |
| Invite to one's penthouse, say | 34 |
| Invite to the penthouse suite, say | 34 |
| Invite, as to one's apartment | 33 |
| Invite, as to one's penthouse | 33 |
| Invited a lady to the Flower Ball? | 34 |
| Invited to one's penthouse, say | 35 |
| Invitee's obligation, briefly | 33 |
| Invitees to director Frank's party? | 39 |
| Invitees who didn't R.S.V.P., say | 37 |
| Invites in (the door) with a flourish | 37 |
| Invites to one's apartment, say | 35 |
| Invocation-response prayer series | 33 |
| Invoice column after "Qty." | 37 |
| Invoke a dancer to get what one wants? | 38 |
| Involuntary extension of troop tours | 36 |
| Involuntary muscular contraction | 32 |
| Involve as an unwilling participant | 35 |
| Involve, as in a sticky situation | 33 |
| Involved in, with "to" | 32 |
| Involving a large number of people | 34 |
| Involving higher-ups, as a meeting | 34 |
| Involving important people, as a meeting | 40 |
| Involving otherworldly practices | 32 |
| Involving purely intellectual speculation | 41 |
| INXS "Never ___ Us Apart" | 35 |
| INXS "___ You Tonight" | 32 |
| Io's guardian, in Greek myth | 32 |
| IOC's Athlete of the Century | 32 |
| IOC's pick for Athlete of the Century | 41 |
| Iodine in a barber's first-aid kit? | 39 |
| Iolanthe, per Gilbert and Sullivan | 34 |
| Ion and Vue, in the auto industry | 33 |
| Ione of "Say Anything..." | 35 |
| Ionesco's "The Bald Soprano," e.g. | 48 |
| Ionian island off the coast of Albania | 38 |
| Ionic compound used as a preservative in wine | 45 |
| Iowa city named for a Sauk chief | 32 |